Thermal migration towards constructing W-W dual-sites for boosted alkaline hydrogen evolution reaction

Abstract

Tungsten carbides, featured by their Pt-like electronic structure, have long been advocated as potential replacements for the benchmark Pt-group catalysts in hydrogen evolution reaction. However, tungsten-carbide catalysts usually exhibit poor alkaline HER performance because of the sluggish hydrogen desorption behavior and possible corrosion problem of tungsten atoms by the produced hydroxyl intermediates. Herein, we report the synthesis of tungsten atomic clusters anchored on P-doped carbon materials via a thermal-migration strategy using tungsten single atoms as the parent material, which is evidenced to have the most favorable Pt-like electronic structure by in-situ variable-temperature near ambient pressure X-ray photoelectron spectroscopy measurements. Accordingly, tungsten atomic clusters show markedly enhanced alkaline HER activity with an ultralow overpotential of 53 mV at 10 mA/cm2 and a Tafel slope as low as 38 mV/dec. These findings may provide a feasible route towards the rational design of atomic-cluster catalysts with high alkaline hydrogen evolution activity.

Interfaces Decrease the Alkaline Hydrogen-Evolution Kinetics Energy Barrier on NiCoP/Ti3C2Tx MXene

“…The Tafel slope was another standard to reflect the reaction kinetics. 35 Figure 3b displays the composite with a Tafel slope of 77.3 mV dec −1 , larger than Pt/C (41.6 mV dec −1 ) but much smaller than that of NiCoP (87.8 mV dec −1 ) and MXene (223.5 mV dec −1 ), signifying superior kinetics due to the introduction of an interface. The catalytic performance of NiCoP@MXene at RT is comparable to that of previously reported phosphide and MXene-based HER catalysts, such as Ni 0.9 Fe 0.1 PS 3 @MXene (η 10 = 196 mV, Tafel slope = 114 mV dec −1 ), 36 CoP/MXene (η 10 = 116 mV, Tafel slope = 57 mV dec −1 ), 37 and 3D porous CoP/NC (η 10 = 91.7 mV, Tafel slope = 51.4 mV dec −1 ).…”

“…We collected the current signals on the whole sheet and then subtracted the background signals to calculate the net current (i, unit = pA) for the sheet at some temperature. Considering the five color maps were taken on the same NiCoP@MXene sheet within the same scanning time at different temperatures (25,35,45,55, 65 °C), the obtained corresponding net current of 5.1, 8.2, 14.0, 17.6, and 23.1 can be used as indirect parameters for rate constant k. Thermal drift caused by temperature changes for these SECM experiments is precalibrated and compensated. According to the Arrhenius equation, we can draw the Arrhenius plot and obtain E a = 31.9 kJ mol −1 (Figure 4f).…”

Bimetal Modulation Stabilizing a Metallic Heterostructure for Efficient Overall Water Splitting at Large Current Density

“…In particular, the metallic sulfide support for the epitaxial growth of metallic heterostructure could be prepared by phase modulation of MoS 2 with additional Mo implantation. The Mo modulation with the presence of additional Mo-Mo bonding with coordinately unsaturated centers can not only provide active sites for H* and OH* adsorption with reduced water dissociation barrier, that is the kinetically limited step in alkaline medium, [30][31][32] but accelerate the desorption kinetics of H* and OH* with tunable local coordination structures in the alkaline medium. [33] Furthermore, we construct the metallic heterostructure with enhanced bifunctional activities by incorporating Ni into the sulfide framework.…”

An Ultrafast and Stable High-Entropy Metallic Glass Electrode for Alkaline Hydrogen Evolution Reaction

“…The equilibrium distance between the Ni and O atoms in Pt 25 Pd 25 Ni 25 P 25 is closer than that in Pt 65 Ni 15 P 25 and Pd 40 Ni 40 P 20 (2.138 Å vs 2.461 and 2.192 Å), indicating that the electron transferability is enhanced which would promote the H 2 O adsorption capacity. Partial density of states (PDOS) of the MG samples were also calculated to probe the interaction strength between atoms (Figures S10 and S11 in the Supporting Information) . It is noteworthy that the absorbed O atom from the H 2 O molecules has a strong affinity at the Pd site of Pd 40 Ni 40 P 20 with significant hybridization energies centered at −9.9 and −6.4 eV, respectively (Figure S10), whereas a strong left shift of the interaction positions (−10.1 and −6.9 eV) from the Fermi level was observed in Pt 25 Pd 25 Ni 25 P 25 .…”

“…Partial density of states (PDOS) of the MG samples were also calculated to probe the interaction strength between atoms (Figures S10 and S11 in the Supporting Information). 47 It is noteworthy that the absorbed O atom from the H 2 O molecules has a strong affinity at the Pd site of Pd 40 Ni 40 P 20 with significant hybridization energies centered at −9.9 and −6.4 eV, respectively (Figure S10), whereas a strong left shift of the interaction positions (−10.1 and −6.9 eV) from the Fermi level was observed in Pt 25 Pd 25 Ni 25 P 25 . Encouragingly, this strong left shift of the interaction positions away from the Fermi level were also observed for the Ni sites on Pt 25 Pd 25 Ni 25 P 25 and for the O atom from the H 2 O molecules (Figure S11).…”