Efficient Hydrogen Evolution Reaction Research Articles

Sub-2.5 nm monodisperse Mo2C nanoparticles on N-doped carbon: The facet engineering for boosting electrochemical hydrogen evolution

Molybdenum carbide materials have demonstrated remarkable potential in catalyzing the hydrogen evolution reaction (HER). However, further modulation of their performance through simultaneously engineering the size and surface crystal facets remains challenging. Herein, we report the successful fabrication of N-doped carbon-supported monodisperse Mo2C nanoparticles with a size of ∼2.06 nm, exhibiting co-exposed (101)/(102) facets-heterojunction, derived from annealing glycine and ammonium molybdate tetrahydrate. The optimized Mo2C/NC-Amt catalyst exhibits a low overpotentials of 128 mV to achieve the current density of 10 mA cm−2 and a small Tafel slope of 72 mV dec−1 under alkaline solution. By changing the molybdate precursor, the phase and crystal facet composition of molybdenum carbide can be effectively tuned, which provides a good platform for studying their structure-activity in HER. The theoretical calculations reveal the synergistic effect of (101)/(102) facets-heterojunction accelerates electron transfer and regulates the d band center of Mo2C, reducing the reaction barriers of intermediates in the HER process, thus significantly boosting reaction activity. This work proposes a novel insight into the rational fabrication of efficient HER catalysts through facet engineering toward heterojunction construction under the 2.5 nm region.

Ru2P/Ir2P Heterostructure Promotes Hydrogen Spillover for Efficient Alkaline Hydrogen Evolution Reaction

AbstractEfficient and durable electrocatalysts toward alkaline hydrogen evolution reaction (HER) are of great significance for the widespread application of anion‐exchange membrane water electrolyzer (AEMWE). Numerous single‐phase catalysts, such as Ru2P, have been explored as efficient HER catalysts; however, many have failed to overcome the inherent sluggish kinetics of the two separate steps involved in the alkaline HER: water dissociation and hydrogen production. In this study, density functional theory calculations are conducted to identify promising combinations of Ir2P and Ru2P materials that promote fast cascade water dissociation and H2 production via kinetically favorable hydrogen spillover from the Ru2P surface to the adjacent Ir2P. An unprecedented construction of Ir2P cluster‐decorated Ru2P hollow nanotubes (c‐RP/IP HNTs), which feature a cooperative heterostructural synergy are developed. This configuration shows greater performance than commercial Pt/C, achieving an overpotential of 23.2 mV at 10 mA cm−2 and maintaining long‐term stability for 55 h in half‐cell tests. Furthermore, the practical AEMWE test, incorporating c‐RP/IP HNTs, demonstrated a remarkable single‐cell performance of 12.23 A cm−2 at 2.0 V and operated stably under 1.0 A cm−2 for over 250 h. This surpasses that of the state‐of‐the‐art proton‐exchange membrane WE.

Hierarchical multiphase heterointerfaces Ni2P–CoP/MoO2 catalyst for efficient and stable hydrogen evolution reaction over the entire pH range

The development of pH-versatile, high-performing, and durable catalysts for hydrogen evolution reaction (HER) is crucial to satisfy the complex environment of water electrolysis industry. Herein, we present the synthesis of a hierarchical multiphase heterointerfaces Ni2P–CoP/MoO2 nanocatalyst with exceptionally high HER activity in the entire pH range through a facile three-step process involved hydrothermal, electrodeposition, and in situ phosphating treatment. Experiments and characterization revealed the strong electronic interactions among the phases of Ni2P, CoP, and MoO2, which endowed the Ni2P–CoP/MoO2 with high hydrogen evolution activity in different pH ranges. Meanwhile, the layered structure of our as-prepared catalyst makes the massive exposure of active sites. As a result, the Ni2P–CoP/MoO2 catalyst shows remarkable performance, requiring mere overpotentials of 33, 41, and 23 mV to drive 10 mA cm−2 in 1 M KOH, 1 M phosphate buffer solution, 0.5 M H2SO4, respectively. Moreover, the catalyst exhibits excellent stability in the chronopotentialmetry test under different pH electrolyte. Impressively, the Ni2P–CoP/MoO2 catalyst coupled with Ni–Fe LDH to form an overall water splitting system only require 1.50 V to drive 10 mA cm−2. Furthermore, this system actuated by wind and solar energy can stably undergo a continuous production of hydrogen and oxygen.

Pt-Decorated bimetallic PdRu nanocubes with tailorable surface electronic structures for highly efficient acidic hydrogen evolution reaction

Efficient and stable catalysts are crucial for green hydrogen production from acidic water splitting. Herein, using interface engineering, the surface electronic structures of bimetallic PdRu nanocubes have been significantly regulated by Pt atoms (PdRu@Pt). Interestingly, Pt atoms are located on the corners and facets of PdRu nanocubes, resulting in lattice tension and fast electron transfer. As a result, the obtained trimetallic PdRu@Pt nanocubes with an average size of 13 nm have exhibited highly enhanced catalytic activity and stability for hydrogen evolution reaction (HER) in acidic media, delivering 18 mV lower overpotential to reach a current density of 10 mA cm−2, and maintaining a remarkable long-term stability for up to 24 h. In particular, the lower overpotential of 489 mV at 500 mA cm−2 for PdRu0.04@Pt0.12 nanocubes indicates its potential for future industrial application in the future. Such enhancements in HER performance can be attributed to the highly facet-edge-exposed Pt atoms and the significant strain effects resulting from the introducing Pt atomic layers to PdRu surfaces.

Hydrogenation of Covalent Organic Framework Induces Conjugated π Bonds and Electronic Topological Transition to Enhance Hydrogen Evolution Catalysis.

Recently, many topological materials have been discovered as promising electrocatalysts in chemical conversion processes and energy storage. However, it remains unclear how the topological electronic states specifically modulate the catalytic reaction. Here, the two-dimensional metal phthalocyanine-based covalent organic framework (MPc-COF) is studied by ab initio thermodynamic calculations to clearly reveal the promotional effect on the electrochemical hydrogen evolution reaction (HER) induced by topological gapless bands (TGBs). We find that the prehydrogenated (and fluorinated) H4CdPc-COF(F) shows the best HER performance, with 0.016 V (near zero) overpotential. By tracking changes to the electronic structure and free energy as the prehydrogenation and HER processes occur, we are able to separately attribute the high HER efficiency in part due to the increase of the electron bath by donating electrons to the conjugated π bonds and also to the existence of TGBs. Specifically, the significant catalytic promotion by TGBs is proven to decrease the free energy by 0.218 eV to near zero. When the TGBs are destroyed, e.g., by replacing N with P and opening a band gap, the HER efficiency is reduced. This study opens avenues for deterministically harnessing topological band features to improve electrocatalysis.

Bimetallic electrocatalysts based on polyoxometalate for hydrogen evolution and urea oxidation reaction

Electrochemical water decomposition is an efficient and environmentally friendly method for producing hydrogen. Because of the high voltage required for water electrolysis, using anodic urea oxidation process (UOR) to replace the oxygen evolution reaction can significantly cut energy usage. In this paper, hydrogen evolution reaction (HER) and urea oxidation process (UOR) electrocatalysts were synthesized by one-step carbonization using giant polyoxomolybdate cluster Mo132 and triethylamine at different temperatures. Ni/MoN@NC obtained at 800 °C shows good HER effect in the acidic electrolyte, an overpotential of 94 mV can provide the current density of 10 mA cm−2. Ni/NiO@NC obtained by calcination at 400 °C exhibits good UOR performance, in which the potential is 1.41 V when the current density is 10 mA cm−2. Efficient HER performance depends on the synergy of Ni and MoN. The highly efficient UOR is derived from the hierarchical structure of Ni and NiO. Furthermore, the porous structure also enhances the full contact between electrolyte and active sites, the catalytic performance of the catalyst was improved benefit to improve the catalytic activity. This work affords a general approach to simply synthesize efficient hydrogen producing materials for HER and small molecules oxidation fields.

Material Engineering Strategies for Efficient Hydrogen Evolution Reaction Catalysts.

Water electrolysis, a key enabler of hydrogen energy production, presents significant potential as a strategy for achieving net-zero emissions. However, the widespread deployment of water electrolysis is currently limited by the high-cost and scarce noble metal electrocatalysts in hydrogen evolution reaction (HER). Given this challenge, design and synthesis of cost-effective and high-performance alternative catalysts have become a research focus, which necessitates insightful understandings of HER fundamentals and material engineering strategies. Distinct from typical reviews that concentrate only on the summary of recent catalyst materials, this review article shifts focus to material engineering strategies for developing efficient HER catalysts. In-depth analysis of key material design approaches for HER catalysts, such as doping, vacancy defect creation, phase engineering, and metal-support engineering, are illustrated along with typical research cases. A special emphasis is placed on designing noble metal-free catalysts with a brief discussion on recent advancements in electrocatalytic water-splitting technology. The article also delves into important descriptors, reliable evaluation parameters and characterization techniques, aiming to link the fundamental mechanisms of HER with its catalytic performance. In conclusion, it explores future trends in HER catalysts by integrating theoretical, experimental and industrial perspectives, while acknowledging the challenges that remain.

Synthesis of Stable and Efficient Electrocatalysts for Hydrogen Evolution: Hierarchical NiMo-Based Hollow Nanotubes

Large-scale development of low-cost, efficient, and stable powder electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solutions is a key step toward commercial hydrogen production. Herein, a hierarchical NiMo-MoO3-x hollow nanotube (NiMo-MoO3-x-HNT) with bifunctional groups as an efficient HER electrocatalyst was strategically invented using an MoO3 nanorod (MoO3−NR) as the precursor. The synthesis mechanism of the NiMo-MoO3-x-HNT is established based on in-depth investigations using diffraction, spectral, and microscopy results. Experimental results suggest that the NiMo-MoO3-x-HNT exhibits excellent electrocatalytic HER performance in 1 M KOH, with a low overpotential of 26.5 mV@10.0 mA cm-2 and a small Tafel slope of 32.6 mV dec–1. These values are comparable to those of cutting-edge electrocatalysts based on platinum-group metals. Moreover, it exhibits an almost unaffected cyclic stability over 50,000 cycles and robust durability over 98 h. This remarkable performance is attributed to its bifunctional groups and the porous hierarchical hollow nanotubular morphology. In summary, this study proposes a novel, efficient, and cost-effective strategy for the development of noble metal-free, high-performance HER electrocatalysts.

Bimetallic Nitride Ni3Mo3N Microrods with Abundant Catalytic Sites Used as Efficient Electrocatalysts for Hydrogen Evolution Reaction

Abstract The importance of efficient and stable hydrogen evolution reaction (HER) electrocatalysts for hydrogen production in alkaline conditions to energy crisis resolution and environmental pollution is immense. In general, the quantity of catalytic sites in the electrocatalyst limits the current density of HER. In response to such problems, the bimetallic effect of non-noble bimetallic nitrides has been shown to regulate the corresponding catalytic sites. Here, a microrod-like non-noble bimetallic nitride catalyst with Ni3Mo3N microrods uniformly modified on nickel foam was synthesized by hydrothermal and nitriding processes. The catalyst showed high catalytic activity for HER in 1M KOH solution. The overpotential was only 28 mV at a current density of 10 mA·cm-2, demonstrating exceptional electrochemical performance. Furthermore, it exhibited remarkable long-term stability under the same current density. This work will open up a low-cost and simple way for the synthesis of bimetallic nitrides as functional electrode materials for HER and electrochemical detection.

Electronic Structure Engineering of Pt-Ni Alloy NPs by Coupling of Gold Single Atoms on N-Doped Carbon for Highly Efficient Oxygen Reduction Reaction and Hydrogen Evolution Reaction.

Improving the catalytic activity and durability of platinum-based alloy catalysts remains a formidable challenge in the context of renewable energy electrolysis applications. Herein, a facile and rapid photochemical deposition strategy for the synthesis of gold single atoms (Au SAs) anchored on N-doped carbon is presented. These Au SAs serve as a charge redistribution support for Pt-Ni alloy nanoparticles (PtNiNPs/AuSA-NDC), creating an extended electron-donating interface with Pt-Ni alloy sites. Consequently, the PtNiNPs/AuSA-NDC hybrid catalyst manifests exceptional catalytic performance and durability in both the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) under acidic conditions. Specifically, in ORR, it exhibits a half-wave potential (0.92V vs RHE), with a mass activity 20.4 times superior to Pt/C at 0.9V. In HER, PtNiNPs/AuSA-NDC demonstrates a notably reduced overpotential of 19.1mV vs RHE at 10mAcm-2 and a mass activity 38 times higher than Pt/C (at 0.25mV). Furthermore, this hybrid catalyst displays outstanding durability, with only an 8.0mV decay observed for ORR and a 6.9mV decay for HER after 10000 cycles. Theoretical calculations provide insight into the mechanism, demonstrating that isolated Au sites effectively modulate the electronic structure of Pt-Ni alloy sites, facilitating intermediate adsorption and enhancing reaction kinetics.

Multiple phase transformation of ZIF-L to LDH and Ag nanoparticles decorated on CoNi layered double hydroxides for high-performance supercapacitor and highly efficient hydrogen evolution reaction

ZIF-L-derived binary layered double hydroxide (LDH) established active catalysts have been shown to have potential as electrode materials in the development of high-performance supercapacitors (SCs) and hydrogen evaluation reactions (HER). This study uses conductive nano-silver (Ag) particles in hierarchically integrated CoNi-LDH nanosheets (NSs), which are described. The developed Ag@CoNi-LDH NSs electrode has a very high specific capacitance of 2878 F g−1 at 0.5 A g−1 and an impressive rate capability. This is due to consistent morphology, plentiful electroactive sites, homogeneous particle size, and decreased electronic/ionic impedance. The fabrication of solid-state hybrid supercapacitors (HSCs) using Ag@CoNi-LDH NSs as the positive electrode and activated carbon (AC) as the negative electrode in PVA/KOH polymer gel electrolytes has been described. The prepared supercapacitors achieve a maximum energy density of 105 Wh kg−1 at power densities of 1183 Wh kg−1, coupled with excellent initial capacitance retentions of 97 % after 20,000 cycles. Ag@CoNi-LDH NSs demonstrate effective electrocatalytic activity towards HER with an ultra-low overpotential of 26 mV at 10 mA cm−2 and the associated Tafel value of 35 mV dec−1 using 0.5 M acidic electrolyte. It is possible to attribute the extraordinary electrochemical performance to the thoughtful mixture of two electroactive materials in the future.

One-step hydrothermal synthesis of nanowire-like W/Mo-Ni3S2/NF electrocatalysts for highly efficient hydrogen evolution reactions

The design of nanostructures and the adjustment of components are very important to improve the performance of hydrogen evolution electrocatalysts. In this paper, Ni, W and Mo trimetallic catalysts are studied from the aspects of morphology, structure and electronic transfer, and a better combination of hydrogen reaction efficiency is obtained. The W/Mo co-doped nickel sulfide electrocatalyst was synthesized on Ni foam by one-step hydrothermal method. As anticipated, the individual incorporation of either tungsten (W) or molybdenum (Mo) into the electrocatalyst did not yield satisfactory enhancements in hydrogen evolution reaction (HER) performance. However, when both W and Mo were co-doped onto the electrocatalyst, a significant improvement in catalyst material performance was observed. Hence, the coexistence of W and Mo is the key to improve HER electrocatalytic activity. In 1 M KOH solution, the W/Mo-Ni3S2/NF electrocatalyst exhibited exceptional HER activity with an overpotential of only 136 mV at a current density of 10 mA·cm−2 and demonstrated excellent cycle stability exceeding 20 hours. In this paper, the strategy of bimental co-doping composite is adopted to adjust the structure of nickel sulfide, which provides reference value for the design of reasonable and efficient HER electrocatalyst.

Synthesis of nitrogen and sulfur bi-doped carbon obtained from spent sapelli wood sawdust and polyhydric alcohol with improved catalytic activity for hydrogen evolution reaction

Developing an efficient water electrolysis system is an important solution for on the development of highly active, cost-effective, and stable electrocatalysts. Carbon-based metal-free catalysts are one of the promising candidates for this purpose. Herein, we present a facile strategy to synthesize and characterize nitrogen and sulfur co-doped porous carbon (NS-PC) from spent sapelli wood sawdust and polyhydric alcohol (xylitol) for efficient hydrogen evolution reaction (HER) in alkaline electrolyte. The resultant NS-PC metal-free catalyst exhibits porous structure, high surface areas and enhanced HER performance with lowest Tafel slope of 68.1 mV dec−1. The enhanced performance is due to the high porosity of carbonaceous material and co-existence of active species (N in the forms of graphitic-N, pyridinic-N, pyrrolic-N, and S in the forms of C–S–C) induced by the maximum carbon-carbon bond polarization, charge re-distribution in the carbon matrices with a synergistically HER activity. In addition, this work provides a versatile and effective strategy for synthetizing excellent carbon-based metal free catalysts from the low cost biowaste for large-scale production of hydrogen through HER.

Construction of Pt Single-Atom and Cluster/FeOOH Synergistic Active Sites for Efficient Electrocatalytic Hydrogen Evolution Reaction

Construction of Pt Single-Atom and Cluster/FeOOH Synergistic Active Sites for Efficient Electrocatalytic Hydrogen Evolution Reaction

Recent advances in electrocatalysts for efficient hydrogen evolution reaction

Recent advances in electrocatalysts for efficient hydrogen evolution reaction

3D printed CuFe2O4 electrode with dominant facet (111) for boosting hydrogen evolution performance

The utilization of hydrogen energy is an important way to low carbon economy, and the development of active electrodes is the most critical step for efficient hydrogen evolution reaction. With the addition of KNO3 as a capping agent, the exposed crystal facet of CuFe2O4 is regulated, and the crystal facet (111) becomes dominant. Compared to CuFe2O4 (3 1 1), CuFe2O4 (111) exhibits low barrier of water dissociation and suitable *H binding strength, resulting in high intrinsic activity. Furthermore, the 3D printed electrodes show more excellent performance. At 3D printed CuFe2O4 (111) electrode, the overpotential is only 152 mV (vs. reversible hydrogen electrode) at 100 mA cm−2, and Tafel slope is as low as 33 mV dec-1. In addition, 3D printed CuFe2O4 (111) electrodes shows high stability. The superior performance of 3D printed CuFe2O4 (111) electrodes originates from high intrinsic activity and more exposed active sites. This study provides a new path for the development of efficient, stable and inexpensive monolithic catalyst electrodes for alkaline hydrogen evolution.

Tailoring Si12C12 nanocluster with late first-row transition metals: A promising approach during single-atom catalysis toward hydrogen evolution reaction (HER)

Hydrogen evolution reaction (HER) has gained a great interest in recent years because it provides the cleanest fuel (H2). One of the most demanding things required for this reaction is an efficient and cost-effective catalyst. Single atom catalysis is one of the most remarkable strategies in this regard. Herein, transition metals adsorbed silicon carbide nanocages (TM@Si12C12; TM = Zn, Fe, Co, Cu, Ni) are investigated as single atom catalysts in order to search less expensive electrocatalysts with excellent efficiency for HER. The pure and hydrogen adsorbed TM@Si12C12 show geometric and thermodynamic stability which illustrates their practical utility. Interaction energies obtained range from −0.70 to −5.73 eV, and it is suggested that Cu@Si12C12 may play an excellent role in HER due to its lowest Gibbs free energy of −0.17 eV (near to zero). In this work, we investigated electronic properties through natural bond orbital (NBO) analysis of selected TM@SiC. According to NBO calculations, it is observed that charge is transferred from adsorbed transition metals towards nanocage. After H adsorption, NBO charge is transferred to hydrogen which shows the adsorption properties of H. In case of HOMO-LUMO energy gap, it is observed that transition metal adsorbed complexes have small energy gaps between 2.17 and 2.77 eV but after adsorption of hydrogen, this energy gap increases to lie in the range of to change from 2.93 to 3.12 eV, which also verified the electronic stability of H adsorbed species. The noncovalent interactions are estimated through NCI analysis. The density of states analysis gives insight about the energy states of occupied and unoccupied orbitals of electrons. The highest thermodynamic stability and electronic conductivity of transition metal adsorbed silicon carbide suggested it as an excellent supportive surface for HER.

Molybdenum-doped tungsten nitride coated with carbon shell and cobalt hydroxide nanosheets for efficient alkaline hydrogen evolution reaction

Water electrolysis is currently the most important way to achieve large-scale hydrogen (H2) production. Although many nonprecious electrocatalysts possess promising catalytic performance at low current density below 50 mA cm−2, it remains a substantial challenge to realize H2 production at industry-compatible current density over 500 mA cm−2. Here we have designed a hierarchical heterostructure of molybdenum-doped tungsten nitride coated with carbon shell and cobalt hydroxide nanosheets (Mo-WN@NC@Co(OH)2) for alkaline hydrogen evolution reaction (HER) with industrial current density and stability. The hybrid exhibits efficient alkaline HER activity, reaching the current density of 500 mA cm−2 at an overpotential of 196 mV. The Co(OH)2 nanosheets and Mo doping endow the composite with more active sites and enhanced intrinsic activity of the catalyst, as well as an appropriate water dissociation energy. In addition, the free energy of activation for each step during the HER process suggests a synergistic effect of Mo doping and Co(OH)2 in Mo-WN@NC@Co(OH)2 promoting surface Volmer and Heyrovsky steps during the HER process. This doping and interfacial engineering methods hold great promise for fabricating efficient nitride-based electrocatalysts for electrochemical energy devices.

Cost-efficient sunlight-driven thermoelectric electrolysis over Mo-doped Ni5P4 nanosheets for highly efficient alkaline water/seawater splitting

Thermoelectric water spitting to hydrogen systems has great potential in the production of environment-friendly fuel using renewable solar energy in the future. In this work, we prepared porous nanosheet Mo doping Ni5P4 catalysts on nickel foam with efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance in alkaline media. DFT calculations and experimental studies have shown that Mo doping deadeneds the interaction between H and O atomic orbitals of transition state water molecules, effectively weakening the activation energy of H2O dissociation. Therefore, Mo doping is favorable for enhancing HER activity with overpotential at 10 mA cm–2 of 93 mV and Tafel slope of 40.1 mV dec–1 in 1 M KOH. Besides, it exhibits high alkaline OER activity with an ultra-low overpotential of 200 mV at 10 mA cm–2. Moreover, this catalyst only needs 1.537 V in a dual-electrode configuration of the electrolytic cell, which is much lower than the commercial Pt/C-RuO2 couple (1.614 V). In addition, we have developed and constructed a solar thermoelectric generator (TEG) that is capable of floating on water. This TEG has a continuous power output and an exceptionally long lifespan, providing a stable power supply to the synthesized catalyst electrolyzer. It can produce a maximum power output of over 90 mW, meeting the requirement of converting solar radiation heat into usable electricity. As a result, the system achieves productivity of 0.11 mL min–1 H2. This solar thermal energy conversion technology shows the possibility of large-scale industrial production of H2 and provides a new idea for exploring heat source utilization.

Bifunctional colloid based on anchoring reactions in-situ modified electrodes: For electrochemical sensing and HER

In this study, a bifunctional [PtCl6]2−-GO colloidal material was prepared by anchoring [PtCl6]2− by abundant oxygen-containing functional groups in protonated graphene oxide. Two modification strategies, surface overcoating and electrochemical in situ deposition, were adopted to modify the screen-printed carbon electrode (SPCE), foam electrodes (CuF, NiF), respectively, and Pt-rGO, which uniformly covered the electrode surface, was obtained by a simple onestep of reducing [PtCl6]2−-GO. The effectiveness of the modified materials and electrode modification strategies prepared was validated by tinidazole electrochemical detection and hydrogen evolution reaction (HER). The results indicated that the Pt-rGO modified SPCE possessed lower LOD and higher sensitivity for the detection. Furthermore, as for HER, optimized Pt-rGO-modified NiF and CuF required only 26 mV and 76 mV overpotentials in alkaline and acidic solutions, respectively, to obtain current densities of 10 mA cm−2. This was largely ascribed to the synergistic interaction between platinum and rGO, with the synthesized platinum-rGO displaying stronger active sites and higher intrinsic activity. In particular, Pt, which acts as an active center, could offer part of its electron to H2O and adjacent reduced graphene oxide sites, thus promoting strong electrical connections and efficient HER kinetics.