Catalysts For Hydrogen Production Research Articles

The influence of nanostructure and electrolyte concentration on the performance of nickel sulfide (Ni3S2) catalyst for electrochemical overall water splitting

Developing non-precious nanostructured electrocatalysts, exhibiting high catalytic activity in combination with excellent stability, has an enormous potential to replace noble-metal-based catalysts for Hydrogen production through electrochemical water splitting. In this study, a facile method is used for the synthesis of three different hierarchical nanostructures of nickel sulfide (Ni3S2) including nanosheets, nanorods, and multiconnected nanorods that are directly grown on 3D nickel foam (NF). These nanostructured electrocatalysts are evaluated for electrochemical water splitting in alkaline media using four different concentrations to understand the effect of nanostructure and ion concentration on the efficiency. Among different combinations of structure and electrolyte concentration, the Ni3S2 in the form of nanosheets exhibited the best electrocatalytic performance for hydrogen evolution reaction (HER) as well as oxygen evolution reaction (OER) in 3.0 M alkaline solution. The hierarchical Ni3S2 nanosheets exhibited a high electrochemically active surface area, which facilitated the charge transport phenomenon along the electrode–electrolyte interface in a higher electrolyte concentration that improved the reaction kinetics so as overall water splitting. The developed Ni3S2 nanosheets required an overpotential of 110 mV (@10 mA cm−2) and 211 mV (@100 mA cm−2) for HER and OER, respectively in 3.0 M electrolyte concentration. This work provides insight into how the materials’ nanostructures and electrolyte concentration could be utilized to improve the electrocatalytic performance for an overall water-splitting process, and the concept could be applied for material designing and conditions optimization for other catalytic applications.

Au decorated chemically exfoliated g-C3N4 as highly efficient visible light catalyst for hydrogen production

The demand for photocatalytic hydrogen production through water splitting is continuously increasing as the world is seeking cleaner and sustainable energy solutions. Herein, we report a comparative study of the as-fabricated Bulk g-C3N4 (BCN), chemically exfoliated g-C3N4 (ECN) and Au-decorated chemically exfoliated g-C3N4 (Au/ECN) photocatalysts for visible light-driven catalytic hydrogen production. To understand the structural, morphological, chemical, and electronic properties of the as-fabricated photocatalysts, XRD, TEM, Raman, PL, XPS, FTIR, UV and EPR analysis was performed. The as-prepared Au/ECN photocatalyst revealed exceptional visible light catalytic performance by producing 410 μmol·g−1 of hydrogen, which is 27.3- and 9.3-fold enhanced compared to those of the CN (15 μmol·g−1) and ECN (44 μmol·g−1) photocatalysts, respectively. This improved visible light-driven catalytic performance of the Au/ECN photocatalyst for hydrogen production is due to the enhanced specific surface area via the chemically exfoliated layered sheets, promoted light absorption due to the decrease in band gap via the effect of surface plasmon resonance attributable to decorated Au nanoparticles, and efficient separation of charge carriers at the interfacial contact. The photocatalytic recyclable experiments indicate excellent stability of the Au/ECN photocatalyst for H2 evolution. These findings reveal the effect of chemical exfoliation and Au decorating on the catalytic efficiency of g-C3N4-based photocatalysts, revealing potential functions for green hydrogen production under the standard visible light illumination.

Dual-function macroalgae biochar: Catalyst for hydrogen production and electrocatalyst

In the current study, Enteromorpha intestinalis, a green macroalgae, has been utilized as a substrate to synthesise a new environmentally friendly and cheap dual-functional (catalyst and electrocatalyst) material. The catalyst was used for efficient hydrogen production from alcoholises sodium borohydride and as an anode catalyst for direct methanol fuel cell applications. At the catalyst synthesis stage, orthogonal arrays of Taguchi is used to find the optimum levels of independent variables for the superior catalyst performance that bears the modest kinetics. The experiments performed in accordance with the L16(45) type orthogonal array. The samples treated at relatively moderate acid, impregnation temperature, impregnation time, burning temperature and burning time showed higher catalytic activities with Exp(5) presenting the optimal catalytic activity followed by Exp(1), Exp(15), Exp(8) and Exp(12), respectively. The experimental levels of coded variables (acid molarity, impregnation temperature and time, burning temperature and time) for Exp(5) were 3 M, 50 °C, 24 h, 500 °C and 2 h., respectively. These finding suggest that providing maximum levels of each of independent variable will not provide high catalytic activity. Taking into account the binary and ternary interactions is an efficient way to determine optimal level of each parameter with regards to maximum hydrogen production rate. The morphological and structural characterization of the optimal catalyst was finally carried out with SEM- EDS, XRD and FT-IR. CV and EIS measurements were taken to determine the electrocatalytic activity of final biochar. Experimental studies revealed that the utilization of E. intestinalis-based electrocatalyst as an anode catalyst for direct fuel cell applications is promising. By employing advanced Taguchi-based experimentation, this research establishes the optimum levels of independent variables, enhancing the catalyst's performance, and highlighting a novel approach to modest kinetics improvement.

The ultra-low energy barrier for photocatalytic hydrogen evolution by the creation of Z-scheme SnC/PtSe2 heterojunctions: First-principles calculation

In this study, we designed a vertical heterojunction of SnC/PtSe2 to lower the energy barrier for the photocatalytic hydrogen evolution reaction (HER). Through first-principles calculations, we systematically explored the electronic structure properties, band bending, photocatalytic performance, and light absorption. Our results indicate that photo-generated carriers transfer along the Z-path, exhibiting strong reduction ability and effective carrier utilization. The observed electric field and band bending at the interface facilitate the recombination of photo-generated electron-hole pairs between layers. As a result, photo-generated electrons accumulate on SnC, enabling the continuation of the HER. Specifically, the SnC/PtSe2 heterojunction demonstrates a significantly reduced energy barrier of 0.081 eV for the HER. Furthermore, SnC/PtSe2 heterojunctions also greatly enhance the absorption of infrared and visible light. Our findings provide valuable insights for the development of catalysts in hydrogen production through water photolysis.

Engineering oxygen vacancies on Tb-doped ceria supported Pt catalyst for hydrogen production through steam reforming of long-chain hydrocarbon fuels

Steam reforming of long-chain hydrocarbon fuels for hydrogen production has received great attention for thermal management of the hypersonic vehicle and fuel-cell application. In this work, Pt catalysts supported on CeO2 and Tb-doped CeO2 were prepared by a precipitation method. The physical structure and chemical properties of the as-prepared catalysts were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, H2 temperature programmed reduction, and X-ray photoelectron spectroscopy. The results show that Tb-doped CeO2 supported Pt possesses abundant surface oxygen vacancies, good inhibition of ceria sintering, and strong metal-support interaction compared with CeO2 supported Pt. The catalytic performance of hydrogen production via steam reforming of long-chain hydrocarbon fuels (n-dodecane) was tested. Compared with 2Pt/CeO2, 2Pt/Ce0.9Tb0.1O2 and 2Pt/Ce0.5Tb0.5O2, the 2Pt/Ce0.7Tb0.3O2 has higher activity and stability for hydrogen production, on which the conversion of n-dodecane was maintained at about 53.2% after 600 min reaction under 700 oC at liquid space velocity of 9 ml·(g cat)–1∙h–1. 2Pt/CeO2 rapidly deactivated, the conversion of n-dodecane was reduced to only 41.6% after 600 min.

Expression of concern: Acceleration of ammonium phosphate hydrolysis using TiO2 microspheres as a catalyst for hydrogen production.

Expression of concern for 'Acceleration of ammonium phosphate hydrolysis using TiO2 microspheres as a catalyst for hydrogen production' by Ayman H. Zaki et al., Nanoscale Adv., 2020, 2, 2080-2086, https://doi.org/10.1039/D0NA00204F.

Hydrogen production catalysed by atomically precise metal clusters.

Atomically precise metal clusters that possess the exact atom number, definitive composition, and tunable geometric and electronic structures have emerged as ideal model catalysts for many important chemical processes. Recently, metal clusters have been widely used as excellent catalysts for hydrogen production to explore the relationship between the structure and catalytic properties at the atomic level. In this review, we systematically summarize the significant developments concerning metal clusters as electrocatalysts and photocatalysts for hydrogen generation. This review also puts forward the challenges and perspectives of atomically precise metal clusters in electrocatalysis and photocatalysis in the hope of providing a valuable reference for the rational design of high-performance catalysts for hydrogen production.

Medium entropy alloy wavy nanowires as highly effective and selective alcohol oxidation reaction catalysts for energy-saving hydrogen production and alcohol upgrade

Au-doped PtAgRhCu alloy wavy nanowire electrocatalysts deliver ultrahigh mass activity and selectivity for alcohol oxidation, enabling energy-saving hydrogen production and selective alcohol upgrading via alcohol-assisted water electrolysis.

Bifunctional PdMoPt trimetallene boosts alcohol-water electrolysis.

Substituting oxygen evolution with alcohol oxidation is crucial for enhancing the cathodic hydrogen evolution reaction (HER) at low voltages. However, the development of high-performance bifunctional catalysts remains a challenge. In this study, an ultrathin and porous PdMoPt trimetallene is developed using a wet-chemical strategy. The synergetic effect between alloying metals regulates the adsorption energy of reaction intermediates, resulting in exceptional activity and stability for the electrooxidation of various alcohols. Specifically, the mass activity of PdMoPt trimetallene toward the electrooxidation of methanol, ethylene glycol, and glycerol reaches 6.13, 5.5, and 4.37 A mgPd+Pt -1, respectively. Moreover, the catalyst demonstrates outstanding HER activity, requiring only a 39 mV overpotential to achieve 10 mA cm-2. By employing PdMoPt trimetallene as both the anode and cathode catalyst, we established an alcohol-water hybrid electrolysis system, significantly reducing the voltage requirements for hydrogen production. This work presents a promising avenue for the development of bifunctional catalysts for energy-efficient hydrogen production.

Rare-metal single atom catalysts for large scale hydrogen production under actual operating conditions

The electrocatalytic hydrogen evolution reaction (HER) is an efficient technology for hydrogen production that holds great significance for the development of renewable energy economies. Rare-metal-based catalysts are considered benchmark catalysts...

Rational design principles of single-atom catalysts for hydrogen production and hydrogenation

This review summarizes the research progress of single-atom catalysts (SACs) in hydrogen production and hydrogenation, and proposes the rational design principles of SACs for hydrogen production and hydrogenation firstly.

Dual-productive photoredox cascade catalyst for solar hydrogen production and methylarene oxidation

A photoredox cascade catalyst for concurrent organic synthesis and hydrogen production was developed by combining a dual-dye sensitized Pt-TiO2 photocatalyst and an N-hydroxyphthalimide hydrogen atom transfer catalyst.

Graphitic carbon nitride supported Ni-Co dual-atom catalysts beyond Ni1(Co1) single-atom catalysts for hydrogen production: a density functional theory study.

Using density functional theory calculations we investigate the formation, structure and electronic properties of gh-C3N4-supported Ni-Co (Ni-Co/gh-C3N4) dual-atom catalysts and Ni1(Co1) single-metal catalysts, as a paradigmatic example of single-atom versus few-atom catalysts. An inverted mold assumption is proposed to identify the factors determining the number, shape and packing manner of metal atoms inside the pores of gh-C3N4. The area matching between virtual fragments and metal fillers and lattice inheritance from N coordination and metal aggregates allow for a stable Ni-Co/gh-C3N4, which would possess more active sites and a more complex structure-activity relation than single-atom doping. The hydrogen production behavior and catalytic activity of this catalyst are comprehensively discussed. Ni-Co/gh-C3N4 exhibits higher hydrogen evolution activity than Ni1(Co1)/gh-C3N4 at an appropriate H coverage, which is comparable to Pt under analogous conditions. This strategy, derived from the inverted mold assumption, is deemed to be a simple and easy-to-operate method for designing and building metal aggregates confined inside the pores of two-dimensional materials and in the cavities of nanoparticles for few-atom catalysts.

First-principles-based microkinetic modeling of methanol steam reforming over Cu(111) and Cu(211): structure sensitive activity and selectivity.

The development of hydrogen energy is widely recognized as a key approach to addressing the energy and carbon emission challenges. Methanol steam reforming is a promising hydrogen production scheme that can provide high-purity hydrogen. In this work, we studied the primary reaction mechanisms of methanol steam reforming over the Cu(111) and Cu(211) surfaces using density functional theory (DFT) calculations and microkinetic simulations. A detailed kinetic perspective on the reaction mechanism, which is often overlooked in previous research that relies solely on DFT calculations, is provided in the current work. Our findings reveal that under typical experimental conditions, the dominant mechanism on the Cu(111) surface is the methyl formate mechanism, while the H2COO dehydrogenation mechanism is dominant on Cu(211). The activity over the Cu(111) surface was slightly higher than that over Cu(211). Based on the degree of rate control analysis results, a reaction rate equation was derived to quantitatively explain the trend of activity under different operating conditions. It was also found that CO2 selectivity was significantly higher over Cu(211) than over the Cu(111) surface. Furthermore, based on the Wulff construction scheme, copper nanoparticle models with different sizes were constructed, and a detailed structure sensitivity study was executed. This comprehensive investigation sheds light on the mechanisms of methanol steam reforming reactions over the Cu(111) and Cu(211) surfaces, providing essential insights for the design of high-performance catalysts for hydrogen production.

HER catalytic activity and regulation of a transition metal atom-anchored BC3 monolayer: a first-principles study.

An atomic-level understanding of the hydrogen evolution reaction (HER) on a transition metal (TM) atom-anchored 2D monolayer is vital to explore highly efficient catalysts for hydrogen production. Here, the catalytic activities and modulation of TM atom (Ti, Fe, Cu, Zn, Mo, Ag, Au)-doped BC3 monolayers are investigated by first-principles calculations. Au@BC3 and Fe@BC3 are proven to be potentially excellent HER catalysts. Partial oxidation engineering on Zn@BC3 could improve its performance. Au@BC3 and Ti, Cu and Mo-anchored BC3 with the support of a NbB2 (0001) surface are expected to replace Pt due to the Gibbs free energy changes extremely close to zero. It is revealed that the catalytic activity of the adsorption site is highly related to the degree of charge transfer between the adsorption site and substrate.

In situ growth of NiSe2 nanoparticles on g-C3N4 nanosheets for an efficient hydrogen evolution reaction

NiSe2/g-C3N4 nanocomposite catalyst exhibits superior hydrogen evolution performance, offering a cost-effective and sustainable alternative to noble metal-based catalysts for hydrogen production.

Amphiphilic, phosphonic acid-capped cadmium selenide quantum dots sensitize a thiomolybdate catalyst for hydrogen production.

Combining a molecular thiomolybdate cluster, [Mo3S13]2-, with cadmium selenide quantum dots capped with tetraethyleneglycol monomethyl ether phosphonate (TEGPA) ligands results in a highly active photocatalytic system for the production of hydrogen under visible light irradiation. The system reaches turnover numbers exceeding 30 000 and remains active for ∼200 h.

Efficient perovskite oxide@CdS composite catalysts for hydrogen production from oilfield wastewater electrolysis

SCF@CdS composite electrocatalysts with a core–shell structure were successfully synthesized using a simple in situ co-precipitation method. These composite catalysts showed superior electrocatalytic activity in both 1 M KOH and oilfield wastewater.

Recent progress in molecular transition metal catalysts for hydrogen production from methanol and formaldehyde.

Hydrogen is considered as a potential alternative and sustainable energy carrier, but its safe storage and transportation are still challenging due to its low volumetric energy density. Notably, C1-based substrates, methanol and formaldehyde, containing high hydrogen contents of 12.5 wt% and 6.7 wt%, respectively, can release hydrogen on demand in the presence of a suitable catalyst. Advantageously, both methanol and aqueous formaldehyde are liquid at room temperature, and hence can be stored and transported considerably more safely than hydrogen gas. Moreover, these C1-based substrates can be produced from biomass waste and can also be regenerated from CO2, a greenhouse gas. In this review, the recent progress in hydrogen production from methanol and formaldehyde over noble to non-noble metal complex-based molecular transition metal catalysts is extensively reviewed. This review also focuses on the critical role of the structure-activity relationship of the catalyst in the dehydrogenation pathway.

Unveiling the potential of amorphous nanocatalysts in membrane-based hydrogen production.

Hydrogen, as a clean and renewable energy source, is a promising candidate to replace fossil fuels and alleviate the environmental crisis. Compared with the traditional H-type cells with a finite-gap, the design of membrane electrodes can reduce the gas transmission resistance, enhance the current density, and improve the efficiency of hydrogen production. However, the harsh environment in the electrolyser makes the membrane electrode based water electrolysis technology still limited by the lack of catalyst activity and stability under the working conditions. Due to the abundant active sites and structural flexibility, amorphous nanocatalysts are alternatives. In this paper, we review the recent research progress of amorphous nanomaterials as electrocatalysts for hydrogen production by electrolysis at membrane electrodes, illustrate and discuss their structural advantages in membrane electrode catalytic systems, as well as explore the significance of the amorphous structure for the development of membrane electrode systems. Finally, the article also looks at future opportunities and adaptations of amorphous catalysts for hydrogen production at membrane electrodes. The authors hope that this review will deepen the understanding of the potential of amorphous nanomaterials for application in electrochemical hydrogen production, facilitating future nanomaterials research and new sustainable pathways for hydrogen production.