Search Results (532)

The efficient photocatalytic generation of hydrogen peroxide (H₂O₂) from pure water remains a formidable challenge, primarily due to the rapid recombination of photogenerated electron–hole pairs and insufficient redox potentials inherent in single-component photocatalysts. To address these issues, we designed and synthesized a heterojunction material comprising cadmium sulfide nanoparticles loaded on carbon spheres (CS@CdS). Under conditions utilizing pure water and ambient air, the CS@CdS composite achieves an H₂O₂ production rate of 1305 μmol·g⁻¹·h⁻¹, which is 3.1 and 3.6 times higher than that of pure CdS and CS, respectively, without the need for any sacrificial agents or external oxygen supply. Systematic characterization reveals that CS and CdS form a tightly coupled electronic interface, which significantly accelerates charge carrier separation and effectively prolongs the lifetime of photogenerated carriers, thereby boosting photocatalytic performance. Furthermore, the CS component extends the visible-light absorption range of the composite and functions as an electron acceptor to suppress charge recombination, collectively endowing CS@CdS with enhanced photocatalytic activity. Mechanistic studies indicate that H₂O₂ production over CS@CdS proceeds predominantly via a two-step single-electron oxygen reduction reaction (ORR) pathway. This work offers a viable strategy for constructing CS-based heterojunction photocatalysts for efficient H₂O₂ synthesis. Full article

Efficient, low-cost catalysts are required for on-demand H₂ generation from chemical hydrides. This study utilized piezoelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers (NFs) as a support to encapsulate bimetallic Co–Mo nanoparticles (NPs) for H₂ production via sodium borohydride (SBH) methanolysis. The PVDF-HFP membranes were synthesized through electrospinning, followed by in situ SBH reduction, which resulted in the uniform dispersion of amorphous Co–Mo NPs within the nanofibrous matrix. The optimized CoMo-0.2@PVDF-HFP membrane exhibited a hydrogen generation rate (HGR) of 1.9 × 10³ mL·min⁻¹·g⁻¹ (Co) at 298 K, indicating a 3.6-fold improvement relative to monometallic Co. Kinetic studies showed a nearly first-order relationship with catalyst dose and a nearly zero-order relationship with respect to SBH concentration, suggesting kinetics controlled by surface saturation. The activation energy (E_a) was determined to be 14.03 kJ·mol⁻¹. Moreover, the catalyst maintained over 80% of its original activity after five cycles. This enhanced performance is attributed to the combined effects of Co and Mo, the amorphous nature of the active sites, and the piezoelectric polarization of PVDF-HFP during mechanical stirring, which together improve charge transfer and reduce NP agglomeration. Full article

Graphitic carbon nitride (CN) is considered a promising metal-free photocatalyst due to its adjustable electronic band structure and straightforward synthesis. Nevertheless, the practical utility of pristine CN is hindered by its rapid carrier recombination rate and low electrical conductivity. In this study, we enhanced CN’s molecular structure through copolymerization with organic molecules, thereby optimizing its crystallinity, resulting in significant improvements. The optimized photocatalyst, termed CNBM, demonstrated a remarkable hydrogen evolution rate of 23.13 mmol·h⁻¹·g⁻¹, a 118-fold increase compared to CN, with an apparent quantum efficiency of 87.9% at 420 nm. This notable enhancement in photocatalytic performance can be attributed to the increased surface area, providing more active sites, and the incorporation of barbituric acid through copolymerization into the CN framework, facilitating electron delocalization. Furthermore, the enhanced crystallinity of CNBM promotes the effective separation of photogenerated electron–hole pairs. Full article

During the marine transport of liquid hydrogen, heat ingress leads to the generation of boil-off gas (BOG), which increases the pressure in the liquid hydrogen storage tanks. Effective BOG management is therefore essential to ensure tank safety and minimize hydrogen loss. This study develops a cryogenic compression recovery and storage system for BOG generated during the marine transport of 160,000 m³ liquid hydrogen. The core process involves compressing a portion of the BOG and subsequently utilizing the BOG’s inherent cold energy to cool the compressed hydrogen, ultimately enabling the storage of the final cryogenic compressed hydrogen product. ASPEN-PLUS software was employed to analyze the proposed system’s specific energy consumption (SEC) and ψ (hydrogen density/SEC) for producing cryogenic compressed hydrogen (CcH₂) across a temperature range of 53 to 110 K and a pressure range of 40 to 100 MPa. Seven optimal sets of state parameters were identified for the cryogenic compressed hydrogen product. Based on a specified optimal parameter set of 80 K and 50 MPa, a simulation of the proposed system’s performance yielded a SEC of 2.25 kWh/kg CcH₂ and an exergy efficiency of 87.88% with BOG feed at 53 K and 0.1 MPa, along with the exergy loss and exergy efficiency for each component. Compared to a BOG re-liquefaction system and a MRJT CcH₂ system under identical conditions, the proposed system achieves 31.81% and 64.9% reduction, respectively, in SEC and 17.32% and 94.6% improvement, respectively, in exergy efficiency. Furthermore, the effects of feed temperature and cryogenic compressed hydrogen product mass flow rate on the proposed system’s SEC and exergy efficiency were investigated. Full article

In this study, a multiphysics finite-element model was developed for the deposition of W–C–B coatings in a hot-wall tubular CVD reactor from a gas mixture of tungsten hexafluoride (WF₆), hydrogen (H₂), and trimethylamine borane ((CH₃)₃N:BH₃) at 550 °C and 5 Torr. The aim of this work is to deepen the understanding of reactant transport mechanisms and to optimize the process parameters for obtaining targeted tungsten carbide or boride phases. The simulations were performed in COMSOL Multiphysics (ver. 6.1) using a 2D axisymmetric formulation that couples laminar flow, heat transfer, and multicomponent diffusion, accounting for heterogeneous chemical reactions at the reactor walls. The obtained spatial distributions of reactant concentrations demonstrate precursor depletion along the reactor length. A comparison of the calculated B/W and C/W stoichiometric ratios for 13 operating conditions with experimental data confirms a transition from W and W–B phases at low trimethylamine borane (TMAB) flow rates to tungsten carbide-based coatings at higher flow rates. Furthermore, a parametric sweep was utilized to determine the optimal parameter range for the synthesis of tungsten borides. Full article

A ternary CdS–MoS₂–rGO photocathode was developed to enhance visible light-driven hydrogen evolution through interfacial heterostructure engineering. The composite was fabricated via a solution-based deposition method followed by thermal conversion, resulting in crystalline CdS and MoS₂ phases that were uniformly integrated within a conductive reduced graphene oxide (rGO) framework. Structural and surface analyses (XRD and XPS) confirmed the coexistence of Cd²⁺, Mo⁴⁺, and S²⁻ chemical states without detectable secondary phases. Photoelectrochemical measurements revealed that the ternary architecture significantly improves charge separation efficiency and interfacial charge-transfer kinetics compared to binary and single-component films. The CdS–MoS₂–rGO photocathode exhibited the highest photocurrent density, reduced charge-transfer resistance, and favorable Tafel slope under visible-light irradiation (0.25 sun, neutral electrolyte). Gas chromatography measurements verified that these electrochemical enhancements translate into increased hydrogen production rates, following the trend: CdS–MoS₂–rGO > CdS–rGO > MoS₂–rGO >> rGO. Applied bias photon-to-current efficiency (ABPE) analysis further confirmed improved photon utilization efficiency in the ternary system. The enhanced performance is attributed to synergistic integration of CdS (light harvesting), rGO (rapid electron transport), and MoS₂ (catalytic edge sites), which suppresses recombination and accelerates proton reduction kinetics. These findings demonstrate that rational multi-component heterostructure design is an effective strategy for improving hydrogen evolution rate under mild operating conditions. Full article

Driven by renewable energy, the operating temperatures of alkaline water electrolyzers (AWEs) exhibit significant dynamic variations. Conventional control strategies rely on fixed startup parameters, causing dispatch plans to deviate from actual physical states, which leads to transient over-temperature or startup failures. To address this issue, this paper proposes a dual-layer optimization strategy for multi-electrolyzer systems based on temperature–power adaptation. First, a thermo-electro-hydrogen coupling model is established to quantitatively reveal the dynamic relationship among the initial temperature, startup power, and transition time. This relationship is utilized to construct a dynamic startup boundary, overcoming the limitations of traditional static constraints. Within the proposed framework, the upper layer utilizes a Mixed-Integer Linear Programming (MILP) model to formulate state-switching and baseline power allocation plans derived from short-term forecasts. Concurrently, the lower layer employs the Mongoose Optimization Algorithm (MOA) for real-time rolling optimization, enabling the system to actively perceive temperature variations and adaptively schedule power allocation. Simulations across typical seasonal scenarios validate the strategy’s superiority. In a typical spring scenario, compared to the traditional Daisy Chain and Rotation Control strategies, as well as the Equal Allocation strategy, the proposed approach reduces total startup time and energy consumption by 59.2% and 54.6%, respectively. Furthermore, it increases wind power accommodation rates by 17.7% and 14.2%, and total hydrogen production by 20.0% and 14.9%, respectively. These superior renewable energy utilization and production efficiencies are robustly maintained across typical seasonal scenarios. By actively perceiving actual temperatures for adaptive scheduling, the proposed strategy ultimately ensures synergy and reliability between the control strategy and actual operational constraints under fluctuating conditions. Full article

To reduce renewable output volatility and improve system integration efficiency, this study constructs a coordinated wind–solar–storage–hydrogen framework. The proposed MILP model innovatively integrates electrolyzer power-dependent efficiency and start-up dynamics into a coupled capacity-sizing and dispatch framework and differs from existing MILP models in refined dynamic constraint construction, multi-energy flow coupling, and practical engineering logic constraints. Refined mathematical models are formulated for core components, including wind and photovoltaic units, battery energy storage systems (BESS), and electrolyzers with power-dependent hydrogen production efficiency and operational dynamics. The electrolyzer efficiency peak at 0.25 p.u. input power is calibrated by industrial test data, and the optimization results show strong robustness to the slight deviation of this peak point. Independent control strategies are designed for each electrolyzer, and a capacity optimization model is formulated to maximize system performance. Simulation tests using wind and solar profiles from Northwest China show that the optimized system achieves a renewable energy utilization rate of 96.7%, a BESS capacity of 7 MWh, and a hydrogen storage tank of 3500 kg. Adopting a time-of-use (TOU) electricity pricing mechanism combined with hydrogen sales significantly enhances system efficiency, while expanding power and hydrogen transmission capacities further improves renewable energy integration. These results demonstrate the practical potential of the proposed integrated system for large-scale renewable energy deployment. Full article

The transition to sustainable energy systems requires the effective integration of offshore wind energy with hydrogen production. In this context, the paper assesses the potential for offshore hydrogen production in eight locations, three of which are located in the Black Sea, using data from the ERA5 database (period 2016–2025) at a height of 10 m and then extrapolated to a height of 150 m. The methodology includes estimating the annual energy production for four types of offshore turbines (Siemens Gamesa (Zamudio, Spain) SG 14-236 DD, Vestas (Aarhus, Denmark) V236-15.0, GE (Rotterdam, The Netherlands) Haliade-X 13, and MingYang (Guangdong, China) MySE12-242) and correlating it with six electrolyzer configurations (PEM and AWE) in gross and net scenarios, as well as analyzing the energy compatibility related to the number of electrolyzers. The novelty of the study lies in the integrated multi-site approach and in the direct quantification of the relationship between wind production and electrolysis requirements for different turbine–electrolyzer combinations. The results indicate a variation in gross annual energy production (AEP) in the range of 45.65 to 81.11 GWh/year, while the net scenario, accounting for operational losses, ranged from 37.75 to 67.05 GWh/year, and hydrogen production between 327 and 1075 t/year, highlighting that the optimal performance is determined by the compatibility between turbine and electrolyzer and the specific energy consumption rather than the nominal power. The ${\mathrm{N}}_{\mathrm{net}}$ analysis shows that, in most cases, the energy produced by a single turbine is insufficient for the full operation of large capacity electrolyzers, resulting in a sub-unit utilization rate and necessitating the use of multiple turbines to reach the nominal operating regime. The analysis is limited to a technical assessment based on historical climatological data, excluding economic aspects, grid constraints, and variations in equipment performance over time. The results underscore the importance of integrating the sizing of offshore wind–hydrogen systems with local resources and energy conversion efficiency. Full article

The development of efficient, stable, and sustainably fabricated photocatalysts for solar-driven hydrogen evolution remains a critical challenge in the field. Herein, we report a novel green coprecipitation strategy to synthesize calcium-doped zinc oxide (Ca-ZnO) nanosheets, utilizing cactus juice as a natural, multifunctional medium for the coprecipitation process. This method enables the in situ, tunable incorporation of 3–7% Ca²⁺ ions into the wurtzite ZnO lattice without the use of harsh chemical reagents. Comprehensive characterization confirms that Ca²⁺ substitutionally replaces Zn²⁺, which preserves the intrinsic crystal structure of ZnO well while inducing the formation of uniform nanosheet morphology. This doping strategy effectively modulates the electronic band structure, progressively narrowing the bandgap from 3.19 eV to 2.90 eV and significantly enhancing visible-light absorption. Crucially, the incorporation of Ca²⁺ also generates oxygen vacancies, which serve as efficient electron traps to suppress photogenerated charge carrier recombination. The optimized 5%Ca-ZnO photocatalyst demonstrates a favorable hydrogen evolution rate of 889 μmol·g⁻¹·h⁻¹ under full-spectrum irradiation, with stability, retaining 94.8% of its activity after four cycles. This work not only provides a high-performance material but also establishes a generalizable, sustainable paradigm for the design of advanced semiconductor photocatalysts. Full article

Hydrogen-mediated microbial electrosynthesis (MES) of chemicals from CO₂ relies on effective gas–liquid transfer at the cathode interface, yet the extent to which cathode surface area regulates acetate productivity remains insufficiently quantified. In this study, three identical MES reactors equipped with stainless-steel cathodes of different geometric areas (8 × 1, 8 × 4, and 8 × 16 cm²) were operated at a constant electric current of 0.3 A. The largest cathode significantly accelerated hydrogen mass transfer (k_La = 0.592 h⁻¹), reaching dissolution equilibrium within 3 min, which was nearly twice as fast as the smallest electrode. Upon inoculation with enriched acetate-producing microbial consortia, the 8 × 16 cm²_cathode reactor fed with CO₂ achieved the highest steady-state acetate concentration of 32 g·L⁻¹ produced at a rate of 2.12 g·L⁻¹·d⁻¹, with 94% hydrogen utilization, and 59% coulombic efficiency. In contrast, smaller electrodes exhibited rapid bubble detachment and reduced residence time, thereby limiting microbial gas uptake, and resulting in low acetate productivity. These findings demonstrate that cathode surface area is a key engineering lever controlling both hydrogen availability and electron recovery efficiency in H₂-driven MES. The results provide practical guidance for electrode design and scale-up of CO₂-to-acetate bioconversion via the MES process. Full article

The energy system is transforming in clean, low-carbon, safe, and efficient directions. As a key carrier of energy consumption, the operation optimization of the integrated energy system (IES) in industrial parks has become an important lever for facilitating energy transformation. This paper focuses on the modeling of the operation optimization of the IES, pays attention to the impact of electricity–carbon–green certificate coordination, and studies the operation optimization of the IES considering hydrogen energy utilization. Firstly, the topological structure of IES is analyzed, and a model of the integrated energy system in industrial parks covering multiple energy links, such as electricity, heat, and gas, is constructed. Hydrogen energy conversion units such as electrolyzers, fuel cells, and methane reactors are introduced. Secondly, the impact of electricity, carbon, and green certificate markets on the operation of IES is analyzed, and a green certificate-carbon trading integration mechanism is designed, along with the establishment of a corresponding market trading model. Then, with the system’s energy purchase and sale costs, electricity curtailment costs, carbon market transaction costs, green certificate transaction revenues, and equipment operation and maintenance costs as the core, an IES daily optimization scheduling model is constructed to minimize the overall cost. Finally, the feasibility of the model constructed in this paper is verified through a case study in the industrial park in the north of Dezhou, Shandong Province, and the result shows that the cost of IES is 15,013.7 yuan under the optimal operation schedule. The utilization rate of new power energy reaches 89.6%, and the 2.135 green certificates are converted into the carbon market. Meanwhile, comparative analysis across multiple scenarios and sensitivity analysis of single factors are conducted to discuss the necessity and effectiveness of the factors considered in this paper, providing a decision-making basis and inspiration for managers to carry out IES operation scheduling. Full article

The massive influx and subsequent anaerobic decomposition of pelagic Sargassum on Caribbean coasts release toxic gases, including hydrogen sulfide (H₂S), and pose a real public health hazard, as evidenced by thousands of reported acute exposure cases in Martinique in 2018. To effectively characterize exposure and identify at-risk areas, we utilized the interactive web-based dispersion modeling system C-PORT, representing Sargassum accumulation zones as area sources derived from recent aerial and in situ monitoring data. Inverse modeling, comparing C-PORT output against Madininair observation data from 2024 to 2025, established emission flux rates ranging from 0.45 to 3.58 mg/m² per second for H₂S, depending on Sargassum density. The resulting modeled concentrations exhibit a low average fractional bias (approx. 0.04) when compared to observations. This study demonstrates that C-PORT can be used to estimate spatially resolved concentrations for H₂S, generate health-risk maps for H₂S, evaluate options to mitigate exposure from varying Sargassum intensity levels, and serve as a crucial tool for public health agencies across vulnerable coastal regions. Full article

The generation of high-purity hydrogen via chemical reaction from hydrogen-rich materials is one of the ways in the alternative energy industry. In this approach, the utilization of catalytic materials that possess the capacity to initiate the decomposition of the starting material and the subsequent release of hydrogen is of paramount importance. In this study, nickel/cobalt-plated copper catalysts (NiCo/Cu) are presented, comprising from 4 to 90 wt.% of cobalt as catalytic materials for hydrogen generation via sodium borohydride (NaBH₄) hydrolysis reaction. The NiCo/Cu catalysts were synthesized via electroless deposition from glycine-based baths, utilizing Ni²⁺ and Co²⁺ ions as metal sources and morpholine borane (MB) as the reducing compound. The catalytic performance in alkaline NaBH₄ hydrolysis was found to correlate with the cobalt loading in the coating. The maximum rate of hydrogen production, which was determined to be 14.22 L min⁻¹ gcat⁻¹, was achieved at 343 K for a catalyst composed of 90 wt.% Co. The reaction proceeded with the activation energy of 52.5 kJ mol⁻¹, while the catalyst exhibited high durability, preserving nearly 88% of its initial activity after five successive reaction cycles. The combination of nickel and cobalt, along with their synergistic effect and high efficiency in the borohydride hydrolysis reaction, makes them promising catalysts. Full article

Under high renewable energy penetration, nuclear power units face significant challenges in peak regulation and market clearing due to constraints on minimum technical output and ramping capability. To address this issue, a long-term power system of Guangdong Province in 2035 is taken as the study case, and an energy–reserve co-clearing simulation framework based on Security-Constrained Unit Commitment (SCUC) and Security-Constrained Economic Dispatch (SCED) is established to systematically evaluate the clearing performance of nuclear power and the formation mechanism of residual electricity under multiple market scenarios. On this basis, a nuclear power-coupled Alkaline Electrolysis (AEL) hydrogen production pathway is proposed as a peak-shaving utilization option, and an economic assessment model for nuclear-based hydrogen production is developed to quantify the investment performance under different hydrogen production capacities and operating modes. The results indicate that the integration of an AEL hydrogen production system can effectively alleviate the rigidity of nuclear power output. Under the “12-3-48-3” flexible peak-shaving mode, the residual electricity available for hydrogen production increases by approximately 30% compared with a typical peak-shaving strategy. Under scenarios with low electricity prices and green hydrogen prices, when the hydrogen production capacity is configured at 50–100 MW, the investment payback period is approximately six years, and the project exhibits strong economic robustness against variations in the discount rate. These findings demonstrate that nuclear-based hydrogen production is economically feasible in future power systems with high renewable penetration, providing quantitative support for nuclear flexibility enhancement and the coordinated development of low-carbon energy systems. Full article