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Review

The Role of Tribocatalysis in Friction and Wear: A Review

by
Diana Berman
1,* and
Ali Erdemir
2,*
1
Department of Materials Science & Engineering, University of North Texas, Denton, TX 76203, USA
2
Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
*
Authors to whom correspondence should be addressed.
Lubricants 2025, 13(10), 442; https://doi.org/10.3390/lubricants13100442
Submission received: 5 September 2025 / Revised: 29 September 2025 / Accepted: 3 October 2025 / Published: 8 October 2025
(This article belongs to the Special Issue Tribo-Catalysis)
Browse Figures
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Abstract

When exposed to high contact pressure and shear conditions, the sliding and/or rolling contact interfaces of moving mechanical systems can experience significant friction and wear losses, thereby impairing their efficiency, reliability, and environmental sustainability. Traditionally, these losses have been minimized using high-performance solid and liquid lubricants or surface engineering techniques like physical and chemical vapor deposition. However, increasingly harsh operating conditions of more advanced mechanical systems (including wind turbines, space mechanisms, electric vehicle drivetrains, etc.) render such traditional methods less effective or impractical over the long term. Looking ahead, an emerging and complementary solution could be tribocatalysis, a process that spontaneously triggers the formation of nanocarbon-based tribofilms in situ and on demand at lubricated interfaces, significantly reducing friction and wear even without the use of high-performance additives. These films often comprise a wide range of amorphous or disordered carbons, crystalline graphite, graphene, nano-onions, nanotubes, and other carbon nanostructures known for their outstanding friction and wear properties under the most demanding tribological conditions. This review highlights recent advances in understanding the underlying mechanisms involved in forming these carbon-based tribofilms, along with their potential applications in real-world mechanical systems. These examples underscore the scientific significance and industrial potential of tribocatalysis in further enhancing the efficiency, reliability, and environmental sustainability of future mechanical systems.

Graphical Abstract

1. Introduction

Moving mechanical systems are vital for the well-being of our highly mobile and industrialized society, as they empower everything from flawless transportation and manufacturing to safe and efficient energy production and automation, thus fundamentally sustaining our modern lifestyle. However, these systems are also prone to surface and interface-mediated inefficiencies and degradations mainly caused by wear, scuffing, fretting, corrosion, fatigue, oxidation, and plastic deformation. These problems collectively account for over 70% of all machine failures in global industrial operations [1,2,3]. Additionally, friction between moving mechanical assemblies consumes significant energy and thus reduces the efficiency of most mechanical systems.
Accordingly, addressing friction, wear, and other surface-specific issues in moving assemblies has long been a primary focus of tribologists and lubrication engineers [4,5,6,7,8,9]. Through the continuous design, development, and deployment of advanced lubricants, materials, and surface engineering techniques, notable progress has been made in minimizing friction and wear and hence the energy and material losses in such assemblies in recent decades [10,11]. In particular, various anti-friction, anti-wear, and extreme-pressure additives have been developed by chemists and lubrication scientists, and they have been proven highly effective in protecting sliding and/or rolling contact surfaces against wear, scuffing, and fatigue failures. Furthermore, with the advent of Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) technologies, several superhard and low-friction coatings have been developed and shown to be very effective in reducing surface-specific tribological failures [12,13,14,15,16,17]. These methods produce highly versatile and durable coatings on the surfaces of moving mechanical assemblies, and thus significantly extend their service lives in industrial operations. Some hard coatings, like DLCs, are naturally slick and can provide ultra-low friction and wear even under dry and marginally lubricated sliding conditions.
In mechanical applications, sliding contact interfaces of mechanical systems often undergo cyclic loading and unloading during which normal and shear deformation may occur and thus create nascent or atomically clean metal surfaces. Progressive wear or material removal can also facilitate the creation of atomically clean surfaces, which are often exposed to a large variety of chemical species (such as water molecules, oxygen, airborne hydrocarbon molecules or dust particles, liquid hydrocarbons, chemical additives, etc.) in their surrounding environment. Under sliding contact conditions, these fresh, atomically clean surfaces can easily react with such species to form a chemical boundary film, or “tribofilm,”. In essence, the idea of tribocatalysis is often linked to the development of such tribofilms, especially from such lubricant additives as zinc dialkyl dithiophosphate (ZDDP), tricresyl phosphate (TCP), molybdenum dithiocarbamate (MoDTC), and cyclopropane carboxylic acid (CPCa), among others [11,18,19,20,21,22]. For instance, ZDDP, a well-known anti-wear additive, generally creates a thin, glass-like phosphate-based tribofilm that strongly protects against wear [23,24]. Conversely, friction modifiers like MoDTC promote the formation of a crystalline molybdenum disulfide (MoS2) tribofilm, which shears easily due to its lamellar structure to reduce friction [25,26,27]. However, these traditional anti-friction and anti-wear additives have recently been restricted due to their negative environmental impacts [28]. Specifically, their sulfur and phosphorus contents can adversely affect the performance and efficiency of the after-treatment devices in internal combustion engines. Accordingly, lubrication scientists have actively been searching for more environmentally friendly alternatives to ZDDP and MoDTC additives.
It is essential to understand that ZDDP and MoDTC form chemical tribofilms unique to their molecular structures and chemistry. Despite concerted efforts, modifying these molecules into more environmentally friendly variants has been tricky, as the new tribofilms produced by such variants either did not perform well or provided limited benefits. Instead, recent research has increasingly focused on extracting tribocatalytically driven solid carbon tribofilms directly from the base oil molecules or new carbon-based additive molecules. These tribofilms advantageously result from the hydrocarbon molecules of the oils themselves and hence do not depend on harmful additives. An additional benefit of these solid carbon tribofilms is their compatibility with other functional additives, including nanomaterials, which could further improve friction and wear performance. For instance, some recent studies have explored combining cyclopropane carboxylic acid (CPCa, a carbon-based liquid additive) with materials like NiAl-layered double hydroxide (LDH) nanoparticles. This synergistic approach has led to the conversion of hydrocarbon molecules in lubricating oils into graphitic carbon nanostructures, and thus greatly enhanced friction and wear performance, especially at elevated temperatures [29]. Likewise, catalytically active titanium dioxide nanoadditives and titanium nitride coatings have also been found to promote the formation of such carbon-rich tribofilms from PAO oils blended with MoDTC [30,31].
In previous research, carbon-based thin solid films, including diamond, diamond-like carbon (DLC), carbon nitride, graphene, etc., produced by PVD and CVD, have demonstrated very impressive friction and wear properties. Among others, DLC and graphene have even been shown to enable superlubric sliding regimes (where friction coefficients reach values below 0.01) under both dry and wet sliding conditions [32,33,34,35,36,37]. Most interestingly, some recent studies confirmed that these highly beneficial carbon-based tribofilms can be extracted in situ from hydrocarbon oils and gas molecules through tribocatalysis under ambient air conditions. Specifically, by incorporating catalytically active elements like copper (Cu) or nickel (Ni) into coatings [18,38] or bulk metallic alloys [39], long-chain hydrocarbon molecules in lubricating oils were shown to be catalytically cracked into smaller dimers and trimers. Such smaller units subsequently combined to form solid carbon-based tribolayers on rubbing surfaces [38]. These and other recent developments represent a new and highly promising direction for increasingly demanding tribological applications, including wind turbines, electric vehicles, and space mechanisms. Specifically, with their little or no known adverse environmental impacts compared to traditional ZDDP and MoDTC, such catalytically active additives, coatings, and bulk materials can have a significant positive effect on future lubrication practices, involving hydrocarbon-based lubricants and greases.
The strong influence of catalysis on the thermodynamics and kinetics of chemical reactions is well-established across many industrial and biological systems [40]. This influence primarily hinges on three critical factors: access to catalytically active surfaces that can lower the activation energy for bond formation and/or breakage, the availability of precursor or source materials, and adequate temperature to provide the necessary activation energy. As it happens, most tribological surfaces inherently possess these prerequisites for catalysis to take place. Specifically, frictional energy dissipation can satisfy the activation energy need for tribocatalysis, and the wear can continually create virgin or nascent metallic surfaces where catalytic reactions can favorably occur. Moreover, recent surface engineering advances [18,38,41,42,43,44] demonstrate that tribological surfaces can be intentionally modified or engineered to enhance their catalytic activity further, opening new avenues for controlling the nature and extent of tribochemical processes more effectively and selectively for the most desirable outcomes.
This review highlights recent progress in the design, development, and applications of tribocatalytic systems and surfaces that can offer lower friction and superior wear and scuffing resistance. We also emphasize significant advances made using surface and structural analyses and computational simulations (both reactive and ab initio molecular dynamics), which were crucial for understanding the key underlying mechanisms behind the in situ formation of carbon-based tribolayers and their significantly enhanced friction and wear performance. These catalytically driven tribolayers provide unprecedented flexibility for reducing harmful additives in lubricating oils. More excitingly, they may also facilitate self-healing, leading to fill-for-life functions in future tribological systems, ranging from traditional combustion engines to emerging electric vehicles. By leveraging the new insights gained from these studies, it is hoped that we can strategically design future tribological systems to fully harness the benefits of catalysis in better controlling friction and wear than before, thereby saving energy, ensuring reliability, and protecting the environment.

2. Tribocatalysis Basics

For years, the term tribocatalysis has been associated with a sustainable and cost-effective pathway for applications such as wastewater treatment, carbon dioxide reduction, water splitting, and sterilization [45,46]. Specifically, it was shown that mechanical stimuli achieved by piezoelectric and triboelectric effects can be used to enhance the catalytic degradation of organic pollutants and dyes, even in the absence of light [45,47,48,49]. In these instances, the rubbing of molecules generates triboelectric charges that trigger reactions with adsorbed oxygen or water, thereby accelerating the degradation process [50,51]. Similarly, this same principle can be applied to sterilization technology, where the release of electrons and formation of holes drive reactions with dissolved oxygen and hydroxide in water to generate radicals, effectively killing bacteria [52].
In recent years, tribocatalysis has also gained significant interest from a tribological perspective. Previous research has shown that local asperity temperatures, often called “flash temperatures” due to friction and deformation, can reach nearly 1000 °C during sliding contacts, whether dry or lubricated [53,54]. This transient temperature spike can significantly impact the physical, chemical, and mechanical states of the contacting asperities, especially under high contact pressures and shear conditions. Specifically, frictional heat can provide the activation energy needed for tribocatalysis to proceed on virgin or nascent metallic surfaces created continuously by wear and deformation. Such a catalytic process can further be enhanced, especially when a catalyst metal is present in the bulk or purposely added to the surface, as illustrated in Figure 1 [41]. In general, the role of the catalytic material is to lower the activation energy for C–H bond dissociation and backbone C–C bond scission, thereby facilitating the formation of shorter hydrocarbon fragments [55]. However, the catalysts also influence carbon reconstruction by acting as templates and providing active nucleation sites for carbon growth, thus affecting the final structure of the carbon films.
Recent advances in computational modeling and simulation techniques have greatly enhanced our understanding of how such catalytically active metals or clusters can help form carbon-based tribofilms. Specifically, these simulations show that when catalyst metals (such as Cu or Ni) contact gaseous or liquid hydrocarbons, such as methane or lubricating oil, they promote the dehydrogenation of these hydrocarbon molecules [38,56,57]. In the case of liquid olefins (or oils) [38], these catalysts also cause the random scission of their carbon-carbon backbones, thus forming smaller fragments or dimers and trimers. These fragmented carbon products then recombine and deposit on sliding surfaces, eventually creating a dense, diamond-like carbon-based tribofilm. It was demonstrated experimentally that the growth rate for such films follows an Arrhenius model, being dependent on the applied contact stress and the surrounding temperature:
Γ = Γ0 exp(−(ΔUact − σΔVact)/kBT)
with Γ0 dependent on the nature of the growth species, internal activation of the tribofilm formation energy ΔUact being 0.96 eV, σ equal to the contact pressure, the activation volume ΔVact calculated from the model to be 0.307 Å3, kB being the Boltzmann constant, and T being the absolute temperature. Furthermore, a more detailed theoretical analysis of tribocatalytic activity in a Platinum-Gold (Pt-Au) system unraveled a strong dependence on both temperature and applied load conditions for enhanced tribocatalysis, as shown in Figure 2 [58].
All in all, recent advances in computational modeling and simulation have significantly enhanced our understanding of the fundamental mechanisms driving tribochemistry and tribocatalysis [38,59,60]. In particular, Density Functional Theory calculations have been very instrumental in evaluating the various stages of tribofilm formation on a catalytically active surface. This includes everything from assessing the effectiveness of hydrocarbon molecules’ adsorption on the surface to understanding the specific steps involved in the dissociation and subsequent formation of C-C, C-H, and C-O bonds, ultimately resulting in the formation of carbon-based tribofilms on the surface [61,62,63,64]. Concurrently, molecular dynamics simulations have provided invaluable visualizations of these molecular-level transformations, allowing researchers to better probe or appreciate the contributions of external parameters like temperature and load on such tribofilm formation [44,56,65,66]. The major advantage of the tribocatalysis, in contrast to the more traditional approaches using oil lubricants, additives, solid lubricants, and coatings, is that it is a self-regulating process that activates upon reaching high friction (leading to temperature increase) and high wear (release of catalysts from the coating/composites) regimes. At the same time, it provides an approach for repairing and replenishing the damage only selectively, when and where needed. Nevertheless, there are still certain limitations that exist. Controlling tribocatalytic processes can be challenging when operating parameters are dictated by application requirements, leaving little flexibility to adjust them for optimal tribofilm formation. At the same time, the requirement to introduce catalytic particles can make the approach incompatible with certain materials, such as soft polymers, whose properties may be adversely affected.

3. Representative Case Studies

As evident from the foregoing, a substantial volume of research already exists and confirms the potential benefits of tribocatalysis in tribology. Specifically, coatings and bulk materials incorporating catalyst metals have been proven to be highly effective in turning long-chain hydrocarbon molecules of lubricating oils into carbon-based boundary films or tribolayers. In addition to solid catalysts or surfaces, the positive effects of catalytically active lubrication additives have also been well-documented. These additives were able to initiate tribocatalysis, leading to the formation of carbon-rich tribolayers on sliding surfaces. Here, we highlight some of these cases, emphasizing their potential usefulness in significantly improving the friction and wear performance of sliding contacts.

3.1. Bulk Catalytic Alloys and Composites

The initial idea of tribocatalysis as a method to tackle friction and wear problems likely comes from using chemical additives specifically designed to chemisorb on surfaces and then react with the surfaces to produce a chemical boundary film that reduces wear. Key examples include TCP and ZDDP, which adsorb onto native iron oxide groups and then react further to form highly durable and protective boundary films against wear and scuffing [25]. Iron is a catalytically active metal; without oxygen, its catalytic reactivity can be pretty high and thus can crack hydrocarbon molecules of oils to generate carbon-rich tribolayers [67,68,69,70]. Many other elements that strengthen steels, such as Ni, Co, W, Mo, V, and Cr, are well-known transition metal catalysts. Therefore, all of them can enhance the catalytic reactivity of such steel alloys and other materials. For example, Khan et al. showed that steels rich in Mo, W, and other catalyst elements can readily form protective carbon-rich tribolayers under lubricated sliding conditions [39]. Steels with high chromium content, which have been previously reported to reduce wear [71], also perform well under lubricated sliding conditions. Specifically, Cr2O3 forming on the sliding surfaces was found to promote the formation of solid oligomers and friction polymers from polyalphaolefin and dodecane [39]. Similar findings were observed on fuel-lubricated sliding tests [72]. Specifically, three types of steels, 52100, D2, and CF2 (soft and hardened), were tested against alumina and 52100 steel counterbodies in ethanol and decane liquids. Figure 3 summarizes these test results, showing similar trends in friction and wear across different environments. D2 steel exhibited the least wear among all materials due to the availability of several catalytic elements in its structure. It also showed a very distinct frictional behavior compared to other steel cases. Again, most of these differences can be attributed to the steels’ catalytic alloying element contents, which help form carbon-based tribofilms in the presence of ethanol or decane, and thus provide extra protection during sliding. Raman analysis of wear tracks revealed the formation of carbon-based tribofilms, with softer steels showing higher D band intensity (greater disorder) and harder D2 steel displaying a stronger G band (more ordered carbon structure). The results underscore alloy composition as the primary factor governing wear resistance, as specific elements can catalyze hydrocarbon-to-polymer transformations during sliding. When using the approach of including catalytic alloying elements, it should be taken into account that the need for specific materials may impact the properties of the bulk structures, such as, for example, hardness. However, the large library of the tribocatalytically active materials makes it possible to optimize the selection close to the needs.

3.2. Powders in the Form of Additives or as Mixtures

Studies from Wang et al. and Chang et al. [73,74] showed that magnesium silicate hydroxide (MSH) nanoparticles used as an additive in lubricating oils can form protective carbon-rich tribofilms on steel surfaces. MSH is mainly found in serpentine minerals, and its tribological properties mainly depend on Si-O, Mg-O, and -OH active groups. When these groups become trapped at sliding contact interfaces, under high-pressure and shear conditions, they can help break down oil molecules into diamond-like carbon layers.
Alternatively, black phosphorus has been used as an additive to not only promote the formation of a protective DLC layer against wear but also to facilitate easy shearing and therefore further lower friction and wear at steel-steel and steel-DLC interfaces due to its layered structure [75]. Here, the oxidized BP surface with P═O and P–OH groups helps the adsorption and subsequent cleavage of oleic acid (OA) molecules, ultimately forming a carbon-rich film at the sliding interface under oil lubrication conditions (Figure 4).

3.3. Coatings

The use of hard coatings simplifies both of the previous approaches by providing not only excellent protection against wear but also being able to help with the catalytic decomposition of hydrocarbon molecules of oils into carbon-based tribolayers under lubricated conditions. With advances in PVD and CVD processes, producing such coatings with multiple alloying elements with high catalytic reactivity has become very easy in recent years. In fact, most of the hard nitride coatings nowadays use more than 2 or 3 elements and, in some cases, more than five elements to trigger high-entropy alloying effects [76,77,78]. For example, the in situ formation and continuous repair of protective carbon tribofilms have been significantly enhanced by the use of catalytically reactive metals like Pt [58,79,80], Ni [42,81], Cu [38,82], Fe [83], and Mg in coatings [84]. In one of these cases, researchers compared the lubricated tribological performance of magnetron-sputtered Gold (Au), Silver (Ag), and Copper (Cu) coatings on steel substrates [62]. All three coatings demonstrated remarkable improvements in tribological performance, showing up to a 43% decrease in friction and a 69% decrease in wear width. These impressive results stemmed from forming a carbon-rich polymer-like tribofilm derived from PAO2 oil used in sliding experiments. These catalytic metals can also be successfully incorporated into hard nitride coatings, e.g., MoN-Ag. This integration promotes tribocatalytic activity in oils and alkanes while at the same time maintaining excellent mechanical hardness and robustness during testing [85,86]. Furthermore, with the incorporation of Cu into binary nitride coatings, such as MoVN-Cu and CrCuN, the extraction of carbon-based tribofilms from various hydrocarbon molecules, including alkanes, alcohols, and glycerol, has been increased significantly [61,87,88].
Erdemir et al. [38,81] pioneered synthesizing metal nitride-copper-based coatings to extract highly protective, carbon-rich tribofilms from gaseous and liquid hydrocarbons. The key to this protective tribofilm formation lies in the inclusion of nanoscale catalytically reactive copper grains within the metal nitride matrix, which significantly enhances tribocatalysis by decomposing hydrocarbon molecules during sliding contact. These tribocatalytic coatings illustrate the potential benefits of integrating such reactive species that can continuously replenish worn-away tribolayers at sliding interfaces. More recently, similar coatings, incorporating copper within various metal nitride matrices, significantly improved friction and wear characteristics when tested in alkenes. However, the degree of improvement varied depending on the chain length of alkane molecules [61]. Metal nitride-based hard coatings are widely recognized for their high hardness, toughness, wear resistance, and stability even in highly corrosive and oxidative environments [89,90,91,92]. Consequently, combining them with tribocatalytic elements offers a highly beneficial approach for more enhanced protection against wear in hydrocarbon-based gases (i.e., methane, propane, or natural gas) and oils (i.e., mineral, synthetic, or bio-based oils) [38,81]. Prime examples include MoN-Cu and VN-Cu coatings, produced via Physical Vapor Deposition (PVD) methods. These coatings have been shown to promote the formation of carbon-rich tribofilms in PAO, 5W30 formulated oil (which contains Zinc Dialkyl Dithiophosphate and other additives), and even in an alkyne environment [38,61].
In a similar study involving hydrocarbon fuels [93], a detailed investigation was carried out on the durability of the MoVN-Cu metal nitride nanocomposite coating across different high- and low-viscosity fuels, over a wide range of temperatures, loads, and sliding velocities. The results demonstrated a very robust tribocatalytic effect from the MoVN-Cu coating, leading to superior tribological performance. Post-test analysis of the wear tracks formed during sliding confirmed the in situ formation of carbon-based tribofilms in the presence of both ethanol and dodecane. Additionally, Transmission Electron Microscopy (TEM) of these tribofilms indicated a clear correlation between copper-rich and carbon-rich areas (Figure 5). This observation confirmed that the copper clusters provided the catalytic surface that triggered the formation of such carbon-rich tribofilms.
In another study by Pan et al. [94], the decomposition of PAO10 oil molecules was catalytically activated by the use of a solid TiB2-MoS2 film. The resultant tribofilm consisted of fullerene-like carbon, which was claimed to be responsible for achieving ultralow-friction and wear. This research expanded the existing library of materials that can trigger tribocatalysis capable of even enabling superlubricity.

3.4. High-Entropy Alloys

The high-entropy alloy (HEA) concept has been around in the materials field for more than two decades and has led to the development of myriad new metallic and ceramic materials with impressive properties. From a tribocatalysis point of view, the same concept can also be considered strategically for designing and developing new alloys, providing significantly enhanced tribocatalytic effects. Their inherent ability to combine several elements, in particular, offers multifunctionality in the resulting alloys, including increased capacity to boost tribocatalytic activity at sliding interfaces [95,96,97]. Beyond their tribocatalytic potentials, high-entropy alloys and their nitrides, carbides, and borides can also be very desirable for their superior physical, chemical, thermal, and mechanical properties [98]. A compelling example comes from the work of Wang et al. [97], where 2D HEA nanoflakes air-spray coated onto a steel substrate demonstrated remarkable friction and wear performance. Specifically, such a coating maintained coefficient of friction (COF) values below 0.1 in ambient air, even under contact pressures reaching 936 MPa. The authors attributed these exceptional results to the tribocatalytically induced formation of an amorphous carbon (a-C) tribofilm derived from the residual ethanol molecules.
The innovative application of the high-entropy alloy concept has been further extended beyond metals well into the realm of ceramics, thereby transferring their inherent multifunctionality to a new class of materials [99,100,101]. In a groundbreaking study [90], smooth and hard (CrNbTiAlV)N high-entropy ceramic (HEC) films were deposited on steel substrates. When tested in phytic acid, these HEC films achieved and sustained a superlubricity regime with a coefficient of friction (COF) below 0.004 and ultralow wear for at least 1.25 million reciprocating cycles under a 1.47 GPa contact pressure (Figure 6) [102]. The authors attributed such an extraordinary improvement in tribological performance to the HEC nanocrystal-assisted hydrolysis of phytic acid molecules. This process yielded inositol molecules that were arranged and sheared parallel to the HEC surfaces, alongside phosphoric acid molecules that functioned as a boundary lubricant, collectively lowering and mitigating the friction coefficient below 0.01, thanks to the highly catalytic nature of HEC.

4. Conclusions and Future Perspectives

This review highlighted some of the most recent advances in forming carbon-rich tribofilms on sliding surfaces through tribocatalysis, especially under high contact pressures and shear conditions. Although the concept of tribocatalysis for in situ creation of such tribofilms is still evolving, it has quickly gained significant attention as a promising way to address growing friction and wear problems under harsh tribological conditions. Based on the research outputs presented here, it is clear that tribocatalysis has the potential to overcome some of the drawbacks of traditional methods (Table 1), including those involving environmentally harmful anti-friction and wear and extreme pressure additives. In particular, research so far has shown that tribocatalysis may offer the ability to further reduce or even potentially eliminate the environmentally harmful ZDDP additive from lubricating oils. While ZDDP molecules react with rubbing surfaces to form a protective iron phosphate tribolayer, tribocatalysis creates a unique condition that decomposes hydrocarbon molecules in lubricating oils to form an equally robust and wear-protective carbon-rich tribolayer. Catalytic effects for cracking hydrocarbon molecules can easily originate from the catalytically active alloying elements or dopants integrated into bulk metals or ceramic structures and coatings. It can also come from the catalytically active additives or powder mixtures within a carrier oil. Creating an inert test environment and/or passing electricity through the lubricated contact interfaces has also been shown to enhance tribocatalysis and thus further facilitate the formation of highly protective carbon-based tribofilms on sliding steel surfaces in a more controllable and tunable manner [49,103]. Alternatively, though not yet realized experimentally, there is a potential to control and accelerate tribocatalysis with thermoelectric processes converting thermal gradients into electrical energy and promoting decomposition of the hydrocarbon compounds [104].
These and numerous other studies have demonstrated that the tribocatalysis concept is very effective in achieving impressive friction and wear properties in sliding contacts. Its relatively easy adaptability to diverse operating conditions further underscores its potential for designing more efficient and durable mechanical systems in the future. Through increased adoption of tribocatalysis, the long-sought-after goals of self-repairing sliding surfaces may soon become a reality, as they are well-proven in lab or bench studies. Though most studies focus on sliding contacts, tribocatalysis may emerge as a practical approach for enhancing the performance of machine elements such as full bearing systems, which are typically lubricated with oils and greases, and the inherent sources of hydrocarbons. All in all, tribocatalysis holds great promise for managing friction and wear, thus delivering substantial benefits, including higher efficiency and reliability in future moving mechanical systems. This is especially true for rapidly expanding electric vehicle technology [105,106], where these advancements can be pivotal in further optimizing the performance of their drivetrain components and ultimately attaining fill-for-life lubrication solutions.
Table 1. Overview of tribocatalysis in comparison to other traditional lubrication approaches.
Table 1. Overview of tribocatalysis in comparison to other traditional lubrication approaches.
Lubrication
Approach		ExamplesLubrication MechanismAdvantagesLimitations
LiquidsMineral and synthetic base oils, vegetable or bio-based lubricants, water-based lubricants, fuels, etc. [107,108,109,110,111,112,113,114,115,116]Wetting surfaces, viscous/hydrodynamic lift, shearing in between liquid layersEasy replenishment, disposal, and recyclabilityFailure upon a lubricant starvation regime, not compatible with vacuum and high temperature
Additives in liquid lubricantsTCP, ZDDP, MoDTC, ionic liquids, nano-colloids in oils [117,118,119,120,121,122,123,124,125,126]Tribofilm formation through surface reactions with additivesThe formed tribofilm protects the surface under lubricant starvationDesigned towards specific surfaces, requires certain activation energy, and is not compatible with vacuum or high-temperature environments
PVD/CVD CoatingsCarbide (e.g., WC), nitride (e.g., TiN, CrN, AlN), oxide (e.g., Al2O3) coatings [127,128,129,130,131,132,133,134,135,136,137,138,139,140,141]High mechanical hardness, high resistance to wear and corrosionCompatible with various environments and high-temperature regimesNeed replenishment or re-application due to finite thickness; strong adhesion to the substrate and mechanical and tribological characteristics may extend their lifetime
Solid lubricantsGraphene, BN, boric acid, WS2, and MoS2 flakes [142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161]Shearing of the lamellar planesCompatible with various environments and elevated-temperature regimesNeed replenishment (but easier than coatings); in general, weaker adhesion to the substrates than in the case of coatings
TribocatalysisCatalytic elements in bulk materials, coatings, or powders (e.g., Mo, Ni, Cu, Pt) in the presence of hydrocarbon sources (e.g., liquid: oils, fuels, alcohols; gaseous: methane, ethane, ethanol vapors, and solid: polymers, amorphous carbonIn situ and on-demand formation of carbon-rich protective tribofilmsContinuous replenishment of the protective films through the decomposition of hydrocarbon molecules, compatible with a wide range of ambient air or inert gas environments and high-temperature regimesIncorporation of catalytic materials, control of the tribocatalysis is possible only with adjustment of the operation conditions, compatibility with surface treatment approaches

Author Contributions

Authors (D.B. and A.E.) have equally contributed to this manuscript. All authors have read and agreed to the published version of the manuscript.

Funding

Support for D.B.’s efforts in this manuscript was provided by the National Science Foundation (NSF) (Award No. 2018132). A.E.’s efforts were provided by the Texas A&M Engineering Experiment Station startup funds and the Governor’s University Research Initiative.

Data Availability Statement

Since this is a review article, the data or results used are available through the original source references. The permissions granted by the publishers secure the reuse of these figures in our manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Summary of the tribocatalytic nanocarbon film generation concept on a catalytically active surface for achieving low friction and wear. The source of carbon, provided in gas, liquid, or solid form, undergoes a catalytically driven transformation during sliding into various forms of carbon-based solid lubricants. The right column highlights the examples of carbon-based structures produced during the tribocatalytically driven process: (from top to bottom) amorphous carbon (DLC), onion-like carbon, and graphitic layers. Reproduced with permission from ref. [41].
Figure 1. Summary of the tribocatalytic nanocarbon film generation concept on a catalytically active surface for achieving low friction and wear. The source of carbon, provided in gas, liquid, or solid form, undergoes a catalytically driven transformation during sliding into various forms of carbon-based solid lubricants. The right column highlights the examples of carbon-based structures produced during the tribocatalytically driven process: (from top to bottom) amorphous carbon (DLC), onion-like carbon, and graphitic layers. Reproduced with permission from ref. [41].
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Figure 2. MD-based observation of the tribocatalysis process. (a) MD model of the studied system. (b) Change in the number of bonds as a function of temperature and pressure after 12ns of simulation time. Snapshots of the simulations in the initial configuration (c) and after ~12 ns of shear at contact pressures of 700K at 300 MPa (d) and 2GPa (e). H-C bonds of ethanol molecules are dissociated with increasing temperature and pressure; an increase in the number of Pt-C bonds is observed upon cooling, transforming into graphene. Temperature has a much stronger effect than the contact pressure. Yellow circles highlight examples of molecular fragments which were counted in the simulations: ethanol, water, H-C bonds, and Pt-C bonds. Reproduced with permission from ref. [58].
Figure 2. MD-based observation of the tribocatalysis process. (a) MD model of the studied system. (b) Change in the number of bonds as a function of temperature and pressure after 12ns of simulation time. Snapshots of the simulations in the initial configuration (c) and after ~12 ns of shear at contact pressures of 700K at 300 MPa (d) and 2GPa (e). H-C bonds of ethanol molecules are dissociated with increasing temperature and pressure; an increase in the number of Pt-C bonds is observed upon cooling, transforming into graphene. Temperature has a much stronger effect than the contact pressure. Yellow circles highlight examples of molecular fragments which were counted in the simulations: ethanol, water, H-C bonds, and Pt-C bonds. Reproduced with permission from ref. [58].
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Figure 3. Steady-state friction values and ball and flat wear rates of soft and hard 52100, soft CF2, and soft and hard D2 steel upon testing in ethanol and decane against alumina (a–c, respectively) and 52100 (d–f, respectively) counter bodies. Reproduced with permission from ref. [72].
Figure 3. Steady-state friction values and ball and flat wear rates of soft and hard 52100, soft CF2, and soft and hard D2 steel upon testing in ethanol and decane against alumina (a–c, respectively) and 52100 (d–f, respectively) counter bodies. Reproduced with permission from ref. [72].
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Figure 4. Reduction in the coefficient of friction in steel-steel and steel-DLC tribopairs observed as a result of oBP-promoted formation of carbon/phosphorus oxide tribofilms. Reproduced with permission from ref. [75]. Red color indicates oxygen atoms, grey indicates carbon atoms, white indicates hydrogen atoms, and pink indicates phosphorus aroms.
Figure 4. Reduction in the coefficient of friction in steel-steel and steel-DLC tribopairs observed as a result of oBP-promoted formation of carbon/phosphorus oxide tribofilms. Reproduced with permission from ref. [75]. Red color indicates oxygen atoms, grey indicates carbon atoms, white indicates hydrogen atoms, and pink indicates phosphorus aroms.
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Figure 5. STEM analysis of tribofilm particles formed on the MoVN-Cu coating surface during tribological experiments; (a) HAADF image of tribofilm produced in dodecane environment and adhered to coating surface with corresponding normalized EELS map of (b) Carbon, XEDS map of (c) Copper, and EELS map of (d) Oxygen. The lower left inset image of (a) is a BSE image of the wear track from which the FIB section was collected for TEM analysis. Reproduced with permission from ref. [93].
Figure 5. STEM analysis of tribofilm particles formed on the MoVN-Cu coating surface during tribological experiments; (a) HAADF image of tribofilm produced in dodecane environment and adhered to coating surface with corresponding normalized EELS map of (b) Carbon, XEDS map of (c) Copper, and EELS map of (d) Oxygen. The lower left inset image of (a) is a BSE image of the wear track from which the FIB section was collected for TEM analysis. Reproduced with permission from ref. [93].
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Figure 6. Tribological performance of HEC coating in PA solution. (a) Schematic diagram of a ball-on-plate tribometer. (b) COF results. (c) The average COF of HEC film lubricated with PA solution under different applied loads. (d) The average COF of HEC film lubricated with PA solution at various sliding frequencies under an external load of 2 N. (e) The average COF when evaluated against different counterbodies. (f) The long-duration COF of the HEC film was lubricated with a PA solution. (g) Comparison of the friction coefficient and wear rate of PA solution lubricated (CrNbTiAlV)N film surface with previous work. Reproduced with permission from ref. [102].
Figure 6. Tribological performance of HEC coating in PA solution. (a) Schematic diagram of a ball-on-plate tribometer. (b) COF results. (c) The average COF of HEC film lubricated with PA solution under different applied loads. (d) The average COF of HEC film lubricated with PA solution at various sliding frequencies under an external load of 2 N. (e) The average COF when evaluated against different counterbodies. (f) The long-duration COF of the HEC film was lubricated with a PA solution. (g) Comparison of the friction coefficient and wear rate of PA solution lubricated (CrNbTiAlV)N film surface with previous work. Reproduced with permission from ref. [102].
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Berman, D.; Erdemir, A. The Role of Tribocatalysis in Friction and Wear: A Review. Lubricants 2025, 13, 442. https://doi.org/10.3390/lubricants13100442

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Berman D, Erdemir A. The Role of Tribocatalysis in Friction and Wear: A Review. Lubricants. 2025; 13(10):442. https://doi.org/10.3390/lubricants13100442

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Berman, Diana, and Ali Erdemir. 2025. "The Role of Tribocatalysis in Friction and Wear: A Review" Lubricants 13, no. 10: 442. https://doi.org/10.3390/lubricants13100442

APA Style

Berman, D., & Erdemir, A. (2025). The Role of Tribocatalysis in Friction and Wear: A Review. Lubricants, 13(10), 442. https://doi.org/10.3390/lubricants13100442

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