H2 Production Activity Research Articles

General Synthesis of Single-Crystalline Ta2O5 Nanorods Towards Enhanced Photocatalytic H2 Production Activity.

As a potential candidate for photocatalytic H2 production from water splitting, Ta2O5 catalyst presents suitable conduction and valence band positions, but suffers from poor charge transfer ability, which seriously limits its photocatalytic performance enhancement. Here, a facile and eco-friendly hydrothermal method was developed for the fabrication of one-dimensional (1D) Ta2O5 nanorods using the freshly precipitated tantalic acids as the precursors. An oriented attachment mechanism was proposed for the growth of Ta2O5 nanorods. Moreover, the present synthetic approach was further extended to direct synthesis of nine kinds of alkaline tantalates and alkaline-earth tantalates nanostructures, suggesting its general applicability. A significant increase in activity in photocatalytic H2 production was revealed on 1D Ta2O5 nanorods. The improved photocatalytic H2 production activity of Ta2O5 nanorods was mainly attributed to its 1D nanorods structure with high crystallization and large specific surface areas as well as excellent charge transfer efficiency.

Boosted photothermal-assisted photocatalytic H2 production by dual heat source-based S-scheme heterojunction

With advances in catalytic research, improvement of catalytic efficiency by using photothermal synergies to strengthen the reaction mechanisms has been focused. In this work, a novel photothermal-assisted photocatalytic H2 production system was constructed by loading Co3O4 nanoparticles on surface of black carbon nitride (BCN) nanosheets, served as the dual thermal source to enhance photothermal effect for synergistically assisting in photocatalytic H2 evolution with optimal H2 production rate reached 3.7 mmol g−1 h−1, significantly higher than that of pure carbon nitride (CN) and BCN. Moreover, the S-scheme heterojunction is also formed between Co3O4 and BCN, leading to the optimization of the charge transfer path, which further promotes the improvement of photothermal-assisted photocatalytic H2 production activity. This study provides the design idea of coupling the multi-heat source effect with the heterojunction electron transport for constructing an efficient photothermal-assisted hydrogen production system.

Enhancing photocatalytic hydrogen production from engineered Escherichia coli-biohybrid system via intracellular electron redirection

The development of biotic-abiotic photosynthetic systems is becoming one of the most promising strategies towards the thirsty demand for sustainable energy production. However, considerable efforts are still required to further optimize the design and avoid the utilization of high-value substances while achieving highly efficient hydrogen production. Here we show a way to construct an Escherichia coli (E. coli)-quantum dots hybrid system by expressing ferredoxin (Fd), Fd-NAD(P)+ reductase (FNR), and [FeFe]-hydrogenase ([FeFe]H2ase) as a potential biocatalyst. We reveal that electrons originating from the quantum dots could be redirected through the newly established electron transport chain NADH/NAD+-FNR-Fd to [FeFe]H2ase, which contributes a key mechanism to boost the highest H2 production activity (3149.5 μmol gdcw−1h−1) by only using glycerol as the carbon source. Our work sheds light on the advantages of an intracellular biological hybrid system by combining the photocatalytic capacity with the optimized metabolic power to produce biofuels.

Ingenious regulation and activation of sites in the 2H-MoS2 basal planes by oxygen incorporation for enhanced photocatalytic hydrogen evolution of CdS

The 2H phase of MoS2 has the advantages of stable phase structure and tunable preparation approach, while the unfavorable H adsorption ability at the basal plane sites hinders the H2 evolution performance. Here, we developed an effective strategy for the regulation of the basal plane properties of MoS2 via oxygen doping. It is demonstrated that the Gibbs free energy of hydrogen adsorption (ΔGH*) at the sites in the basal plane can be effectively optimized. Using oxygen-doped MoS2 (OMoS) as a cocatalyst, the constructed OMoS/CdS heterojunction photocatalyst shows a stronger built-in electric field and improved photocatalytic H2 production activity. The optimized OMoS/CdS sample with only 0.3 wt% OMoS loading amount achieved an H2 evolution rate of 58.47 mmol g-1h−1 under AM 1.5 light irradiation, which is significantly superior to that of conventional MoS2 modified CdS and even higher than the 1 wt% Pt modified CdS. Our results not only highlighted the significant potential of OMoS as a photocatalyst for hydrogen production, but also proposed a superior to and effective conception for optimizing the H2 evolution activity at the basal plane sites of 2H-MoS2.

Photocatalytic activity of molybdenum-doped LOS- zeolite for efficient dye degradation and hydrogen production

This research investigates the synthesis and application of Losod-zeolite (LOS-Z), a crystalline hydrated sodium aluminosilicate (Na12Al12Si12O48.xH2O) as a potential photocatalyst for dye degradation and H2 production from dye-degraded water. The photocatalytic properties are enhanced by impregnating molybdenum (Mo) into LOS-Z (Mo@LOS-Z). XRD, FTIR, SEM, EDX, and elemental mapping were used to study the physicochemical properties of synthesized materials while UV–vis and PL were employed to explore the optoelectronic properties. The photocatalytic activities for dye degradation and H2 production were evaluated using methylene blue (MB) under visible light irradiation. An enhancement in the efficiency of dye degradation (56%–82%) and H2 production rate was demonstrated due to the competitive photocatalytic performance of 10% Mo@LOS-Z compared to the pristine LOS-Z and CFA-BFA blend. It exhibited 2.5 times higher (∼1200 μmol g−1h−1) H2 production than the LOS-Z (∼480 μmol g−1h−1) due to the synergistic effects of narrowed band gap and recombination rate. This study could pave the way forward into the synthesis of waste-derived photocatalysts for efficient dye degradation and H2 production.

Molecular dynamics approach to efficient hydrogen generation process of Co-B catalysts decorating lanthanides (La, Ce, Pr, Nd) supported by flat-sheet and twisted ThMoB4-type graphene from NaBH4 hydrolysis: Insights from non-self-consistent GFN1-xTB method

In this study, the promoter role on highly efficient hydrogen generation productivity and H2 formation mechanisms of Co-B-X catalysts modified by rare earths (X = La, Ce, Pr, Nd) supported by flat-sheet and twisted ThMoB4-type graphene from sodium borohydride (NaBH4) hydrolysis was investigated using molecular dynamics (MD) method based on non-self-consistent tight binding GFN1-xTB Method. The twisted ThMoB4-type graphene layer was constructed by adsorbing of ethylene carbonate (EC) molecule on armchair site of graphene surface with applying of geometric optimization process. The addition of Nd to CoB exhibited to higher H2 release compared to other CoB containing lanthanides (La, Ce and Pr) both flat-sheet and twisted ThMoB4-type graphene. While the number of H2 for Co-B-Nd is 14, the H2 amount is only 8 for Co-B-Ce supported flat-sheet graphene at the end of simulation time. Also, the placing of twisted graphene instead of flat-sheet in the catalytic complex led to about 36 % increase in H2 number for Co-B-Nd. The computational results revealed that the availability of the active sites, such as basicity of catalytic environment related to OH and H species and the mobility of Co atom, played an important role for catalytic activity and performance for H2 production. This work can provide new insight for experimental studies of Co-B-X (X = La, Ce, Pr, Nd) catalysts for hydrogen production in atomic-level and the creation of new hydrogen energy applications and facilitates for H2 generation efficiency.

Strong Electron Coupling Effect of Prussian Blue Analogs Derived Ultrathin Nitrogen‐Doped Carbon Wrapped Fe‐CoP for Enhanced Wide Spectrum Photocatalytic H2 Evolution

AbstractWith the advantages of large specific surface area and high porosity of general metal‐organic frame materials, russian blue analogs have broad application prospects in catalysis. In this work, a series of ultra‐thin N‐doped carbon coated Fe‐CoP (Fe‐CoP@NC) are prepared by phosphating Fe‐Co‐Co Prussian blue analogs (Fe‐Co‐Co PBA) in different degrees for the broad‐spectrum photocatalytic hydrogen evolution. The results show that Fe‐CoP@NC‐3 has the highest photocatalytic hydrogen production rate of 16.6 mmol h−1 g−1, which is 83 times greater than that of Fe‐Co‐Co PBA. The excellent stability of Fe‐CoP@NC‐3 is proved by cyclic experiments. The outstanding photocatalytic H2 production activity of Fe‐CoP@NC‐3 can be ascribed to the strong electron coupling effect between Fe‐CoP and N‐doped carbon layer. The photogenerated electrons of Fe‐CoP are transferred to the N‐doped carbon layer, which is electron transport mediator accelerating the electron transfer and synergetic improving the hydrogen evolution efficiency. This work provides an effective strategy for designing an ultra‐thin N‐doped carbon layer coated phosphide photocatalyst with strong electron coupling effect.

Plasmonic tandem heterojunctions enable high-efficiency charge transfer for broad spectrum photocatalytic hydrogen production

Rational engineering of semiconductor photocatalysts for efficient hydrogen production is of great significance but still challenging, primarily due to the limitations in charge transfer kinetics. Herein, a fascinating plasmonic tandem heterojunction with the hc-CdS/Mo2C@C heterostructure is aimfully prepared for effectively promoting the charge separation kinetics of the CdS photocatalyst via the synergistic strategy of phase junction, Schottky junction, and photothermal effect. The difference in atomic configuration between cubic-CdS (c-CdS) and hexagonal-CdS (h-CdS) leads to effective charge separation through a typical II charge transfer mechanism, and plasmonic Schottky junction further extracts the electrons in the hc-CdS phase junction to realize gradient charge transfer. Besides, the photothermal effect of Mo2C@C helps to expand the light absorption, accelerate charge transfer kinetics, and reduce the hydrogen evolution energy barrier. The carbon layer provides a fast channel for charge transfer and protects the photocatalyst from photocorrosion. As a result, the optimized hc-CMC photocatalyst exhibits a significantly high photocatalytic H2 production activity of 28.63 mmol/g/h and apparent quantum efficiency of 61.8%, surpassing most of the reported photocatalysts. This study provides a feasible strategy to enhance the charge transfer kinetics and photocatalytic activity of CdS by constructing plasmonic tandem heterogeneous junctions.

Synthesis of Carbon Nitride Polymorphs by Sacrificial Template Method: Correlation between Physicochemical Properties and Photocatalytic Performance.

Carbon nitride compounds (CNCs) in the form of graphitic carbon nitride (g-C3N4) and poly(heptazine imide) were synthesized using different metal chloride salts (MClx), i.e., NaCl, KCl and CaCl2, as sacrificial templates and by varying the MClx to melamine molar ratios. A systematic study of their photocatalytic activity for H2 production in relation to the physicochemical, morphological, and optical properties was carried out. Each sample was tested achieving the highest hydrogen evolution rates of about 7660 µmol g-1 h-1, 5380 µmol g-1 h-1 and 3140 µmol g-1 h-1 using CaCl2, KCl, and NaCl, respectively. This work demonstrates how the synthesis of CNCs with different MClx leads to the production of high-performance photocatalysts due to a combination of factors as the formation of vacancies or cyano groups, a shift in the optical threshold and tuning of micro(nano)structure. The results demonstrate that, when CaCl2 is used as a sacrificial template, porous and exfoliated g-C3N4 nanosheets are formed leading to hydrogen productions which outperform most of the previously reported g-C3N4 prepared using a single synthetic step.

Pd-CQDs/CdS ternary composite for highly efficient visible light driven H2 evolution under combined action of type I heterojunctions and Schottky junctions

Visible light driven catalytic hydrogen production over CdS based catalysts could be a good candidate strategy to help solve the global energy crisis. To improve the photocatalytic H2 production activity of CdS, the series of Pd nanoparticles and carbon quantum dots (CQDs) co-modified CdS nanorods (NRs) composites were designed to simultaneously build the type I heterojunctions and Schottky junctions. The photocatalytic H2 evolution activities of the samples were assessed under visible light (λ > 420 nm) irradiation and the reaction mechanism was proposed. The Pd-0.35CQDs/CdS catalyst exhibited excellent activity with the average hydrogen evolution rate (HER) of 47.1 mmol h−1 g−1, which is 36.2 times higher than that of the pure CdS. Its apparent quantum efficiency is 17.1% (450 nm light). The combined action of Schottky junctions and type I heterojunctions in the composite Pd-0.35CQDs/CdS greatly promoted charge transfer and separation, resulting in enhancement of the photocatalytic activity. Additionally, the synergistic effect of the Pd nanoparticles and CQDs resulted in enhanced visible light absorption and optimized band structure, helpful to enhancement of the photocatalytic activity. This study provides a simple and cost-effective strategy for improving visible light catalytic H2 production performance of catalysts.

Strain-Driven Phase Transitions in Delafossite Cu1-xAxAlO2: A Key to Enhanced Photo(electro)catalytic Performance.

This study investigates the impact of intrinsic strain and phase transitions on the thermodynamic stability and electronic properties of Cu1-xAxAlO2 solid solutions, which are key to their photocatalytic performance. It is demonstrated that Cu1-xAxAlO2 with A = Ag, Au, Pt can form continuous isostructural solid solutions due to relatively small compressive strain, while a substantial increase strain restricts Cu1-xPdxAlO2 to forming only limited solutions. For A = Li, Na, the formation of heterostructural solid solutions is facilitated by structural motif alterations, accommodating significant differences in ionic radii and A-O bond characteristics. Specifically, Cu1-xLixAlO2 exhibits a phase transition at x ≈ 0.333, whereas Cu1-xNaxAlO2 undergoes three distinct phase transitions. Electronic structure analysis indicates that in Cu1-xAxAlO2 (A = Ag, Au), d10-d10 closed-shell interactions dominate, enabling tunable band gaps with varying solubility. Nevertheless, increased intrinsic strain in metal sublattices, as seen in A = Pd and Pt, shifts antibonding states to the Fermi level, inducing a semiconductor-to-metal transition. Experimental evidence confirms that Ag+ ions modulate the band gaps and carrier dynamics in Cu1-xAgxAlO2, with Cu0.75Ag0.25AlO2 exhibiting heightened photoelectrochemical activity and a 38.5-fold enhancement in H2 production rate over CuAlO2. Additionally, the coordination environment changes between alkali metals and O, induced by phase transitions, effectively tune the band edge positions and carrier dynamics of Cu1-xAxAlO2 (A = Li, Na) heterostructural solid solutions. Therefore, 3R-Cu0.97Li0.03AlO2 with asymmetric nonlinear dumbbell O-Cu-O demonstrates the highest photocatalytic H2 production activity, 72.9 times greater than CuAlO2. In contrast, α-Cu1-xAxAlO2 with a smaller CuO6 octahedral splitting energy exhibits increased band gaps, resulting in diminished photocatalytic activity. This research underscores that strain-driven phase transition provides an additional control factor and new mechanism for regulating the photo(electro)catalytic activity of Cu1-xAxAlO2 solid solutions.

Ultrafast Two-Color X-Ray Emission Spectroscopy Reveals Excited State Landscape in a Base Metal Dyad.

Effective photoinduced charge transfer makes molecular bimetallic assemblies attractive for applications as active light-induced proton reduction systems. Developing competitive base metal dyads is mandatory for a more sustainable future. However, the electron transfer mechanisms from the photosensitizer to the proton reduction catalyst in base metal dyads remain so far unexplored. A Fe─Co dyad that exhibits photocatalytic H2 production activity is studied using femtosecond X-ray emission spectroscopy, complemented by ultrafast optical spectroscopy and theoretical time-dependent DFT calculations, to understand the electronic and structural dynamics after photoexcitation and during the subsequent charge transfer process from the FeII photosensitizer to the cobaloxime catalyst. This novel approach enables the simultaneous measurement of the transient X-ray emission at the iron and cobalt K-edges in a two-color experiment. With this methodology, the excited state dynamics are correlated to the electron transfer processes, and evidence of the Fe→Co electron transfer as an initial step of proton reduction activity is unraveled.

Novel and noble-metal-free CdIn2S4/MoB Schottky heterojunction photocatalysts with efficient charge separation for boosting photocatalytic H2 production

The construction of Schottky heterojunctions by selecting applicable metalloids and semiconductors is highly effective for improving the activity of semiconductors. Herein, we deposited CdIn2S4 on MoB by hydrothermal method to construct a noble metal-free and unreported CdIn2S4/MoB Schottky heterojunction for achieving high photocatalytic H2 production. In ultraviolet photoelectron tests, the Fermi level of the CdIn2S4/MoB composites exhibited a certain shift compared with CdIn2S4 and MoB, manifesting the rearrangement of the Fermi level and the formation of Schottky heterojunction. The formed Schottky heterojunction greatly promoted the electron migration from CdIn2S4 to MoB (proved by XPS tests) to obtain high charge separation efficiency (confirmed by PL and electrochemical tests). CdIn2S4/MoB composites possessed smaller H2 evolution overpotential and Tafel slope, which greatly promoted the release of H2 in the kinetics. Besides, CdIn2S4/MoB composites had higher light absorption capacity and larger specific surface area, which were for more conducive to H2 production. Ultimately, CdIn2S4/MoB composites had significantly improved H2 production activity. Among all composites, the activity of CdIn2S4/20MoB was the highest (463.53 μmol·g−1·h−1), which was 3.5 times that of CdIn2S4-1 %Pt. Besides, CdIn2S4/MoB composites possessed excellent stability in five experiments. Simultaneously, the formation of the Schottky heterojunction and its mechanism of promoting H2 production reaction were also thoroughly investigated. This work is the first to report that MoB could construct Schottky heterojunctions with sulfides for efficient photocatalytic H2 evolution, which is easily extended to sulfides other than CdIn2S4.

Z-scheme promoted interfacial charge transfer on Cu/In-porphyrin MOFs/CdIn2S4 heterostructure for efficient photocatalytic H2 evolution

The rational modulation of charge transfer pathway within heterojunction is essential toward boosting photocatalytic activity for H2 production from water splitting Herein, the bimetallic-modified porphyrin MOFs (CuIn-PMOFs) crystals have been developed as a substrate for the epitaxial wrapping of CdIn2S4 (CIS) nanosheets via a facile solvothermal process to fabricate novel hierarchical CuIn-PMOFs@CdIn2S4 (CuIn-PMOFs@CIS) heterojunctions. The experimental results, combined with density-functional theory calculations, demonstrated that the CuIn-PMOFs have a more negative conduction band position and the electrons transfer pathway is inclined from CIS to CuIn-PMOFs, which leads to the formation of unique Z-scheme heterojunctions. Profiting from the special “O-In” charge transfer channel, extensive highly active photoinduced electrons areaggregated and depleted in the conduction band of CuIn-PMOFs, contributing to the improvement of H2 generation activity. Moreover, the heterojunction model also revealed the minimum Gibbs free energy for H* intermediate adsorption (ΔGH*). Concretely, the optimized composite displayed a maximum H2 evolution rate of 7527.54 μmol g–1h−1, which is around 13.12 and 6.63 times higher than that of pure CdIn2S4 and CuIn-PMOFs, respectively. This work aims to suggest that constructing distinctive Z-scheme modulated charge transfer mechanism is an advanced strategy for acquiring highly efficient photocatalysts.

One step co-deposition of Ni0.96S and Ag2S on TiO2 nanosheets for enhanced photocatalytic H2 generation with superior stability

Introduction of co-catalysts to construct heterojunctions is one of the important strategies to improve the photocatalytic hydrogen production activity of semiconductor catalysts. Here, Ni0.96S and Ag2S co-decorated TiO2 composites were prepared by a simple one-step solvothermal method, whose photocatalytic H2 production activities were evaluated and related H2 evolution mechanism was explored. The 5%Ni0.96S-8%Ag2S/TiO2 ternary composite exhibited much enhanced photocatalytic activity with the photocatalytic hydrogen evolution rate (HER) of 23.67 mmol·h−1·g−1, which is 131.5 fold higher than that of the pure TiO2. Even higher HER, 29.45 mmol·h−1·g−1, was obtained in the presence of 40 mL glycerol. The photocatalytic HERs of the 5%Ni0.96S-8%Ag2S/TiO2 catalyst under visible light (λ > 420 nm) and simulated solar light (AM1.5) were 353.78 and 935.24 µmol·h−1·g−1, respectively. The apparent quantum efficiency (365 nm) is as high as 13.9%. Remarkably, the catalyst exhibited excellent photocatalytic cycling stability and durability, beneficial to practice applications. The improved photocatalytic activity of the composite can be attributed to much improved charge carrier transfer/separation, optimized energy band structure and enhanced visible light absorption caused by synergistic effect of Ni0.96S and Ag2S.

Synergistic Effect of Rutile and Brookite TiO2 for Photocatalytic Formic Acid Dehydrogenation.

Solar energy is an ideal clean and inexhaustible energy source. Solar-driven formic acid (FA) dehydrogenation is one of the promising strategies to address safety and cost issues related to the storage, transport, and distribution of hydrogen energy. For FA dehydrogenation, the O-H and C-H cleavages are the key steps, and developing a photocatalyst with the ability to break these two bonds is critical. In this work, both density functional theory (DFT) calculation and experimental results confirmed the positive synergistic effect between brookite and rutile TiO2 for O-H and C-H cleavage in HCOOH. Further, brookite TiO2 is beneficial to the generation of the •OH radical and significantly promotes C-H cleavage in formate. Under optimized conditions, the H2 production efficiency of FA dehydrogenation can reach up to 30.4 μmol·mg-1·h-1, which is the highest value compared with similar reported TiO2-based systems and over 1.7 times the reported highest value of Au0.75Pd0.25/TiO2 photocatalysts. More importantly, after more than 42 days (>500 h) of irradiation, the system still demonstrated high H2 production activity, indicating the potential for practical application. This work provides a valuable strategy to improve both the efficiency and stability of photocatalytic FA dehydrogenation under mild conditions.

Oxygen deficient BaTiO3 loading sub-nm PtOx for photocatalytic biological wastewater splitting to green hydrogen production

Efficient photocatalytic production of H2 from wastewater rather than pure water is a dual solution to address environmental and energy crises. However, the rapid recombination of photo induced charges in photocatalysts and the inevitable electron consumption caused by organic pollutants pose significant challenges to bifunctional photocatalysis. In this study, we designed an amorphous PtOx supported BaTiO3 single catalyst (named BTPOv-0.09) characterized by oxygen vacancies. This catalyst provides Pt-O-Ti3+ charge separation sites and can effectively generate H2 (1891 μmol · g−1 · h−1), while oxidizing pefloxacin (rate constant k = 0.0485 min−1). It is worth noting that the catalytic performance of BTPOv-0.09 significantly exceeds that of the original BaTiO3, exhibiting 49 and 39 times higher H2 production activity and rate constants (BaTiO3, k = 0.00119 min−1). BTPOv-0.09 exhibits significant H2 production activity in various types of wastewater, highlighting its versatility and promising role in wastewater treatment and renewable energy production.

Constructing multifunctional novel noble-metal free NiS/ZnS/g-C3N4 ternary nanocomposites for highly active superior photocatalytic water splitting

Ultrasound-assisted wet-impregnation approach and cation-exchange hydrothermal method are employed effectively to develop the ternary nanocomposites NiS/ZnS/g-C3N4 (NZ-CN) with promising photocatalytic hydrogen (H2) generation activity. Several analytical techniques are utilized to characterize the as-synthesized NiS/ZnS/g-C3N4 nanocomposites to study their physical and chemical characteristics. The H2 production activity of the synthesized photocatalysts was tested using a 250 W halogen lamp with Na2S (0.25 M) and Na2SO3 (0.35 M) as sacrificial reagents. The optimized NZ-CN7.5% (3% NiS/ZnS/7.5% g-C3N4) catalyst displayed an exceptional H₂ generation rate of 8624 μmol h⁻1 g⁻1, exceeding both, pristine g-C3N4 (by 22.1 times) and 3% NiS/ZnS (by 3 times). This represents the highest reported rate of H₂ evolution for a graphitic carbon nitride (g-C3N4) based ternary nanocomposite under simulated solar radiation. By reusing the used NZ-CN7.5% (3% NiS/ZnS/7.5% g-C3N4) photocatalyst in four consecutive runs, the stability of the catalyst was investigated, and their individual activity in the H2 production activity was assessed. This study provides valuable insights for designing efficient noble metal-free g–C3N4–based photocatalysts, which can significantly contribute to the transition to solar-driven hydrogen generation. Further, we proposed a plausible mechanism for the photocatalytic H2 generation process over the NiS/ZnS/g-C3N4 photocatalyst.

Decorating ZnIn2S4 with earth-abundant Co9S8 and Ni2P dual cocatalysts for boosting photocatalytic hydrogen evolution

Due to the synergistic effect of the rapid transfer of photo-generated electrons and enrichment of reactive active sites, reasonably assembling dual cocatalysts with semiconductor is considered as an excellent method to enhance the photocatalytic properties of semiconductors. Herein, earth-abundant Co9S8 and Ni2P dual cocatalysts modified-ZnIn2S4 (ZIS/CS/NP) composite photocatalyst has been constructed by the low-temperature solvothermal and in-situ photodeposition methods. A series of characterizations indicate the hollow structure of Co9S8 can reduce the charge transfer distance and enhance the migration of photo-generated electrons, while Ni2P acts as an electron collector and provides sufficient active sites for H2 release in this dual cocatalysts system. Because of the synergistic effect of dual cocatalysts, ZIS/CS/NP composites exhibit superior activity in the photocatalytic H2 production compared to blank ZIS, ZIS/CS and ZIS/NP. Notably, the optimal photocatalytic H2 production rate of ZIS/CS/NP reaches 6823.64 μmol g−1 h−1, which is approximately 86 times higher that of blank ZIS. This work is expected to provide useful reference for the construction of high-performance dual-cocatalyst modified semiconductor composite for photocatalytic H2 evolution.

Data analysis and machine learning aided integrated catalyst activity and process modelling for selective H2 production from biomass gasification

Hydrogen energy derived through biomass gasification is considered as one of the most sorted sustainable sources of renewable energy. This process enhances the H2 production from biomass in the presence of specific catalysts. Among different kinds of models that have been employed for this process, ML models adept at approximating non-linear functions and facilitate outcome prediction without detailed mathematical descriptions. Thus, the current work focuses on understanding structural-composition-operating-target property relationships, and integrated catalyst and process modelling using ML framework for thermo-catalytic biomass gasification to H2 production, and demonstrates outliers handling, data normalization for efficient handling of data-driven modelling with non-linear database. Linear, tree-based, kernel-based, and ANN models were developed with 589 datapoints screened from the 59 relevant papers with 24 inputs and 4 outputs (H2, CO, CO2, and CH4 as vol. %). Performance of these models are evaluated through 5-fold cross-validation and test data with the help of statistical measures. ANN with Basian-regularization learning algorithm using tan-sigmoid activation function in both layers, resulted superior performance in prediction of H2 production (RMSE = 6.85 & R2 = 0.80) and other output gases with high accuracy (i.e., minimum deviation from experimental data) compared to other ML models. Further, using the best ML model, input contribution and PDP analysis were performed to interpret the significance of predominate input parameters affecting on the product composition. Feature contribution analysis reveals that temperature, S/B ratio, catalyst support type, and sulphur content in biomass are significant parameters for enhancing H2 production from catalytic-biomass gasification, and PDP analysis discloses their optimal operating region.