Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
8.3
4.5
Journals
Catalysts
Special Issues
Catalysis for Solid Waste Upcycling: Challenges and Opportunities
share announcement

Catalysis for Solid Waste Upcycling: Challenges and Opportunities

A Special Issue of Catalysts (ISSN 2073-4344) belonging to the section "Biomass Catalysis".

Deadline for manuscript submissions: 31 December 2026 | Viewed by 5296

Editors

Dr. Yao He

E-Mail Website
Guest Editor
School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
Interests: thermochemical conversion; catalytic pyrolysis; municipal solid waste
Dr. Kai Li

E-Mail Website
Guest Editor
National Engineering Research Center for New Power Generation, North China Electric Power University, Beijing 102206, China
Interests: biomass and organic solid waste pyrolysis
Special Issues, Collections and Topics in MDPI journals
Dr. Junyan Zhang

E-Mail Website
Guest Editor
Department of Chemical and Biomolecular Engineering & Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD, USA
Interests: upgrading of alcohols to long-chain hydrocarbons on zeolites

Special Issue Information

Dear Colleagues,

The escalating global production of solid waste, along with increasing environmental concerns and the potential depletion of non-renewable resources, has intensified the urgent need for sustainable waste management strategies. Catalytic upcycling of solid waste into value-added products presents a transformative approach to address these challenges, serving as a critical element for achieving the circular economy. This emerging field encompasses the conversion of diverse waste streams, which generally include complex macromolecules in plastics, biomass residues, electronic waste, and industrial byproducts, into renewable fuels, chemicals, and other functional materials through innovative catalytic processes. Despite significant progress in recent years, key challenges remain, such as catalyst design for decomposing complex waste feedstocks, elucidation of reaction network or mechanism, and evaluation of process scalability and economic viability.

This Special Issue, entitled “Catalysis for Solid Waste Upcycling: Challenges and Opportunities”, aims to compile original research papers, critical reviews, and perspective articles that report fundamentals, innovative strategies, laboratory and field experimental studies, and modeling on catalytic technologies for solid waste conversion. The Guest Editors welcome contributions covering, but not limited to:

  • Development of novel catalysts (e.g., heterogeneous, homogeneous, enzymatic) for waste conversion
  • Mechanistic studies and kinetic modeling of waste upcycling processes
  • Integrated catalytic strategies for mixed or contaminated waste streams
  • Life-cycle assessment and techno-economic analysis of catalytic upcycling
  • Case studies on industrial applications and scalable processes

By fostering interdisciplinary collaboration, this Special Issue seeks to accelerate the transition toward sustainable waste-to-resource solutions. Should the authors have any questions on the appropriateness of the topic they work with for submission to this Special Issue, please feel free to reach the Guest Editors for more information.

Dr. Yao He
Dr. Kai Li
Dr. Junyan Zhang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-anonymized peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • solid waste
  • biomass
  • catalytic conversion
  • value-added utilization

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (6 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

Jump to: Review

17 pages, 2457 KB  
Article
Efficient Hydrogen-Rich Syngas Production via Synergistic Tar Cracking and Sorption-Enhanced Steam Gasification of Woody Waste over Ni/CaO Catalysts
by Yao He, Ziming Mo, Jingyong Liu and Zhuowen Xie
Catalysts 2026, 16(8), 728; https://doi.org/10.3390/catal16080728 - 14 Aug 2026
Viewed by 396
Abstract
Steam gasification of woody waste represents a sustainable pathway for addressing environmental issues with energy recovery. However, challenges such as low hydrogen content and high tar yield severely limit the gasification efficiency and hinder its large-scale application. In this study, a composite Ni/CaO [...] Read more.
Steam gasification of woody waste represents a sustainable pathway for addressing environmental issues with energy recovery. However, challenges such as low hydrogen content and high tar yield severely limit the gasification efficiency and hinder its large-scale application. In this study, a composite Ni/CaO catalyst was developed to enhance the yield of H2-rich syngas in woody waste gasification, with Ni loading serving as the active site for catalytic cracking and CaO support as the CO2 sorbent for sorption-enhancement. Ni nanoparticles ranging from 18 to 28 nm in diameter are uniformly distributed on the CaO support. At 700 °C, Ni/CaO with 10 wt.% Ni loading enables the 455.4 mL/g H2 yield with an H2/CO ratio of 1.93, representing increases of 137% and 230%, respectively, compared to non-catalytic conditions. Meanwhile, the tar yield was 12.1 wt.% with an aromatics selectivity of 37%, corresponding to reductions of 50.2% and 54%, respectively. Characterizations confirmed that Ni particles were uniformly distributed on the support in the form of metallic Ni. The Ni active sites promote syngas production by facilitating the cleavage of C-C and C-H bonds in volatiles, while the CaO support enhances H2 generation by shifting the water–gas shift reaction equilibrium forward. This study provides a promising strategy for enhancing hydrogen-rich syngas production from woody waste gasification. Full article
(This article belongs to the Special Issue Catalysis for Solid Waste Upcycling: Challenges and Opportunities)
►▼ Show Figures

Graphical abstract

23 pages, 5535 KB  
Article
Synergistic Photothermal Catalysis over an MOF-Derived Matrix Enabled by Alloy-Coordination Interactions for Sustainable Hydrogen Production from Formic Acid
by Shenghao Li, Siyu Song, Chunlin Ke, Zhengting Gu, Mingzheng Liao and Chao Wang
Catalysts 2026, 16(5), 385; https://doi.org/10.3390/catal16050385 - 27 Apr 2026
Viewed by 560
Abstract
Formic acid (FA) has emerged as a promising liquid hydrogen storage material, yet efficient photothermal dehydrogenation catalysts with high activity and H2 selectivity remain challenging. Herein, a polymetallic synergistic PdCu/M-ZNC (where M represents the co-doped In, Sn and Mo species) is fabricated [...] Read more.
Formic acid (FA) has emerged as a promising liquid hydrogen storage material, yet efficient photothermal dehydrogenation catalysts with high activity and H2 selectivity remain challenging. Herein, a polymetallic synergistic PdCu/M-ZNC (where M represents the co-doped In, Sn and Mo species) is fabricated by molten-salt-assisted pyrolysis of ZIF-8 precursors followed by metal incorporation. The unique molten salt environment effectively preserves the porous architecture of ZIF-8, enabling the secure anchoring of PdCu alloy nanoparticles onto the carbonaceous matrix enriched with M-Nx coordination sites. Under light irradiation, the PdCu alloy sites kinetically accelerated the overall adsorption and activation of FA molecules. Based on empirical observations and corroborated by the established literature, this alloying effect was inferred to facilitate the C-H bond cleavage and HCOO* desorption processes. Concurrently, the M-Nx sites act as efficient electron transfer channels, facilitating the rapid coupling of photogenerated electrons with protons (H+) to evolve H2. Consequently, the optimal catalyst exhibits an enhancement in gaseous product yield (404.46 mmol/g/h) and H2 selectivity (67.49%) at 75 °C. This work offers a catalyst design that aligns with several principles of green chemistry: it maximizes the atom utilization of precious Pd, incorporates synergistic non-precious metals within MOF-derived frameworks to enhance stability, and leverages solar energy to drive hydrogen production under mild conditions, presenting a more sustainable pathway for hydrogen release from liquid carriers. Full article
(This article belongs to the Special Issue Catalysis for Solid Waste Upcycling: Challenges and Opportunities)
►▼ Show Figures

Graphical abstract

19 pages, 2666 KB  
Article
Investigation into the Catalytic Co-Pyrolysis of Chlorella vulgaris and Eucalyptus Branches Using Bimetallic Ni-X (X = Mg, Cu, Fe) Modified HZSM-5: Product Characteristics and Bio-Oil Composition
by Bingquan Tian, Haimin Ning, Mingshan Jiang, Guodong Jia, Shiyi Zhao, Guangsheng Wei and Chunxiang Chen
Catalysts 2026, 16(5), 383; https://doi.org/10.3390/catal16050383 - 27 Apr 2026
Viewed by 609
Abstract
The co-pyrolysis of Chlorella vulgaris (CV) and Eucalyptus branches (EP) offers a promising strategy to enhance bio-oil yield, improve resource utilization efficiency, and alleviate environmental pressures. In this study, the microwave-assisted co-pyrolysis of CV and EP at a mass ratio of 2:1 was [...] Read more.
The co-pyrolysis of Chlorella vulgaris (CV) and Eucalyptus branches (EP) offers a promising strategy to enhance bio-oil yield, improve resource utilization efficiency, and alleviate environmental pressures. In this study, the microwave-assisted co-pyrolysis of CV and EP at a mass ratio of 2:1 was investigated, focusing on the catalytic performance of Ni-X (X = Mg, Cu, Fe) bimetallic modified HZSM-5 zeolites. The effects of these catalysts on pyrolysis characteristics, product distribution, and bio-oil composition were systematically evaluated. Experimental results showed that the 15% Ni-Cu/HZSM-5 catalyst exhibited the best catalytic performance, achieving the highest bio-oil yield of 16.83%; it also elevated the Rm to 0.0687 wt.%/s and reduced Ts to 2084 s. Composition analysis revealed that Ni-Cu/HZSM-5 significantly promoted the formation of hydrocarbons, increasing their relative content from 11.59% (C2E1 Group) to 28.92%, while effectively suppressing the formation of nitrogen-containing compounds, reducing their content by 5.05%. Based on these results, a possible reaction pathway is proposed in which the Ni-Cu/HZSM-5 catalyst may enhance heteroatom removal through hydrodeoxygenation (HDO) at the Ni-Cu sites, followed by cracking and aromatization at the HZSM-5 acid sites. This effect may be complemented by preferential adsorption of oxygenated intermediates over nitrogen-containing species, which could help suppress the formation of nitrogenous heterocycles. This work provides theoretical guidance for the application of bimetallic zeolite catalysts in microalgae/lignocellulose co-pyrolysis, alongside a viable pathway for valorizing Eucalyptus by-products to produce high-quality bio-oil. Full article
(This article belongs to the Special Issue Catalysis for Solid Waste Upcycling: Challenges and Opportunities)
►▼ Show Figures

Graphical abstract

19 pages, 2328 KB  
Article
Precisely Engineered Nitrogen-Doped Hierarchical Porous Carbon from Lignin for High-Rate and Ultra-Stable Supercapacitors
by Zhebiao Xu, Siyu Song, Zhuangjia Chen, Wenzhuo Wang, Yushen Huang, Fudong Bai, Riyang Shu, Zhipeng Tian and Chao Wang
Catalysts 2026, 16(4), 368; https://doi.org/10.3390/catal16040368 - 20 Apr 2026
Cited by 1 | Viewed by 1138
Abstract
The development of high-performance and sustainable carbon electrodes is increasingly important for next-generation supercapacitors, yet controlling heteroatom doping and hierarchical pore evolution in biomass-derived carbons remains a key challenge. Lignin, as an abundant aromatic biopolymer, offers a structurally rich platform for designing functional [...] Read more.
The development of high-performance and sustainable carbon electrodes is increasingly important for next-generation supercapacitors, yet controlling heteroatom doping and hierarchical pore evolution in biomass-derived carbons remains a key challenge. Lignin, as an abundant aromatic biopolymer, offers a structurally rich platform for designing functional carbons, but its rigid cross-linked architecture limits precise pore regulation and efficient nitrogen incorporation. In this work, nitrogen-doped hierarchical porous carbons were engineered from enzymatically treated lignin through a synergistic urea-assisted nitrogen doping and KOH activation strategy. The urea–KOH co-activation drives the coordinated evolution of micropores and mesopores. This approach yields an optimized carbon material possessing a high BET surface area of 2569 m2 g−1, an interconnected micro–mesoporous architecture, and a favorable distribution of pyridinic, pyrrolic, and graphitic nitrogen species. The engineered pore hierarchy is correlated with enhanced ion transport kinetics, as evidenced by a high b value of 0.99 and a capacitive contribution of 98.5% at 100 mV s−1; nitrogen functionalities introduce redox-active sites and improve interfacial wettability. As a result, the selected material delivers a high specific capacitance of 221 F g−1 at 0.5 A g−1, strong rate capability with 84.4% retention at 20 A g−1, and excellent cycling durability with 90.7% capacitance retention after 50,000 cycles. This study demonstrates a potentially mechanistically informed, scalable pathway for coupling enzymatic structural regulation with chemical activation, offering a sustainable route for transforming lignin into high-value carbon electrodes suitable for advanced supercapacitor applications. Full article
(This article belongs to the Special Issue Catalysis for Solid Waste Upcycling: Challenges and Opportunities)
►▼ Show Figures

Figure 1

15 pages, 4022 KB  
Article
Effects of Metal–Acid Proximity on Aromatics Production in CO2-Assisted Catalytic Pyrolysis of Polypropylene over Fe-Modified ZSM-5
by Yao He, Jie Zhang, Renhua Huang, Nanxin Li and Yunwu Zheng
Catalysts 2026, 16(3), 270; https://doi.org/10.3390/catal16030270 - 16 Mar 2026
Cited by 4 | Viewed by 1324
Abstract
CO2-assisted catalytic pyrolysis presents a viable and promising approach to addressing plastic waste pollution and mitigating climate change. However, the effects of the metal–catalyst combination mode and the spatial distance between metal–acid sites on catalytic performance remain unclear. In this study, [...] Read more.
CO2-assisted catalytic pyrolysis presents a viable and promising approach to addressing plastic waste pollution and mitigating climate change. However, the effects of the metal–catalyst combination mode and the spatial distance between metal–acid sites on catalytic performance remain unclear. In this study, the reaction behaviors of the configurations, Fe3O4 and ZSM-5 in tandem catalysis (Fe3O4&HZ), their physical mixture (Fe3O4-HZ), and Fe-loaded ZSM-5 (Fe/HZ), were compared in polypropylene pyrolysis under a CO2 atmosphere. The aromatic contents followed this order: Fe/HZ > Fe3O4-HZ > Fe3O4&HZ > ZSM-5 > Fe3O4. Specifically, Fe/HZ with the highest degree of metal–zeolite proximity achieved an aromatic content of 66.1%, significantly higher than the 34.2% obtained with Fe3O4&HZ, demonstrating that closer metal–acid proximity promoted aromatic formation. Moreover, Fe/HZ significantly reduced coke deposition. Based on characterization results from XRD, SEM, TEM, XPS, and NH3-TPD, the enhanced spatial proximity between metal and acid sites strengthened the functional synergy between iron-based redox sites and zeolitic Brønsted acid sites. This synergy facilitated the reverse water–gas shift reaction of CO2, which consumed hydrogen generated during aromatization and shifted the reaction equilibrium toward enhanced aromatic production. These findings would offer theoretical and strategic insights into the optimization of CO2-assisted catalytic pyrolysis systems for the sustainable upcycling of plastic waste. Full article
(This article belongs to the Special Issue Catalysis for Solid Waste Upcycling: Challenges and Opportunities)
►▼ Show Figures

Figure 1

Review

Jump to: Research

40 pages, 48656 KB  
Review
A Review of the Value-Added Conversion of Biomass Catalyzed by High-Entropy Alloys
by Jinyi Lv, Yidong Wang, Hongyu Zhao, Qingrong Li, Jing Sun, Yingping Pang, Xinyan Zhang, Tao Wang, Yanpeng Mao, Zhanlong Song, Murodbek Safaraliev, Xingxing Cheng and Ziliang Wang
Catalysts 2026, 16(6), 560; https://doi.org/10.3390/catal16060560 - 17 Jun 2026
Viewed by 515
Abstract
The utilization of biomass resources is of significant importance. However, the complexity of biomass thermochemical conversion processes and the performance limitations of conventional catalysts restrict the stable selection of reaction pathways and ultimately affect catalytic yields. With the rapid development of synthesis techniques [...] Read more.
The utilization of biomass resources is of significant importance. However, the complexity of biomass thermochemical conversion processes and the performance limitations of conventional catalysts restrict the stable selection of reaction pathways and ultimately affect catalytic yields. With the rapid development of synthesis techniques and machine learning, nanoscale high-entropy alloys (HEAs) with targeted properties can now be accurately predicted and synthesized. The diverse compositions and structures of HEAs enable versatile catalytic selectivity, while their unique four core effects enhance catalytic activity and stability. This review primarily elaborates on the specific applications of HEAs in biomass thermochemical conversion. It covers the fundamental characteristics of HEAs, preparation methods, and machine learning-driven design strategies. Summarized the directional conversion and value-added research of high-entropy alloys in biomass thermal conversion intermediates. This demonstrates the excellent application adaptability of high-entropy alloys in complex reaction systems. Finally, prospects for the rational design of high-entropy alloy catalysts and their application in biomass refining technologies are outlined. Full article
(This article belongs to the Special Issue Catalysis for Solid Waste Upcycling: Challenges and Opportunities)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-6
Back to TopTop