Highly dispersed Ru nanospecies on N-doped carbon/MXene composite for highly efficient alkaline hydrogen evolution

Hydrogen has emerged as a promising environmentally friendly energy source. The development of lowcost, highly active, stable, and easily synthesized catalysts for hydrogen evolution reactions(HER) remains a significant challenge. This study explored the synthesis of nitrogen-doped MXene-based composite catalysts for enhanced HER performance. By thermally decomposing RuCl_(3) coordinated with melamine and formaldehyde resin, we successfully introduced nitrogen-doped carbon(N–C) with highly dispersed ruthenium(Ru) onto the MXene surface. The calcination temperature played a crucial role in controlling the size of Ru nanoparticles(Ru NPs) and the proportion of Ru single-atom(Ru SA), thereby facilitating the synergistic enhancement of HER performance by Ru NPs and Ru SA. The resulting catalyst prepared with a calcination temperature of 600℃, Ti_(3)C_(2)T_x-N/C-Ru-600(TNCR-600), exhibited exceptional HER activity(η10= 17 m V) and stability(160 h) under alkaline conditions. This work presented a simple and effective strategy for synthesizing composite catalysts, offering new insights into the design and regulation of high-performance Ru-based catalysts for hydrogen production.

Facilitating active species by decorating CeO_(2)on Ni_(3)S_(2)nanosheets for efficient water oxidation electrocatalysis

In the pursuit of stable,high performance Ni-based oxygen evolution reaction(OER)electrocatalysts,modifying the local chemical compositions or fabricating hybrid nanostructures to generate abundant interfaces for improving the water oxidation activity of electrocatalysts has emerged as an effective strategy.Herein,we report the facile development of a Ni_(3)S_(2)-CeO_(2)hybrid nanostructure via an electrodeposition method.Benefiting from the strong interfacial interaction between Ni_(3)S_(2)and CeO_(2),the electron transfer is notably improved and the water oxidation activity of Ni_(3)S_(2)nanosheets is significantly enhanced.In 1.0 M KOH,the Ni_(3)S_(2)-CeO_(2)electrocatalyst achieves a current density of 20 mA cm-2 at a low overpotential of 264 mV,which is 92 mV lower than that of Ni_(3)S_(2).Moreover,Ni_(3)S_(2)-CeO_(2)exhibits superior electrochemical stability.Density functional theory calculations demonstrate that the enhanced OER electrocatalytic performance of Ni_(3)S_(2)-CeO_(2)can be ascribed to an increase in the binding strength of the reaction intermediates at the Ni_(3)S_(2)-CeO_(2)interface.

Continuous Fe^(3+)releasing enabled complete reconstruction of Ni-based MOF for promoted water oxidation in industrial alkali

Most oxygen evolution reaction(OER)electrocatalysts show poor stability under industrial alkaline conditions(20–30 wt.%KOH).Therefore,it is essential to develop stable,efficient,and low-cost OER catalysts for industrial water electrolysis.Herein,we present a straightforward approach for the complete electrochemical reconstruction of Ni-BDC,a Ni-based metal-organic framework,for OER.This method involves the continuous release of Fe^(3+)from Fe foam counter electrode in a high-concentration(6.0 M,25 wt.%)KOH solution.The continuously Fe^(3+)releasing not only realizes in situ Fe^(3+)doping,but also introduces abundant defects in the obtained catalyst during cyclic voltammetry activation,thereby accelerating the electrochemical reconstruction.The reconstructed OER catalyst(Fe-doped nickel hydroxide/oxyhydroxide nanosheets supported on Ni foam,Fe-NiO_(x)(OH)y/NF)manifests a low overpotential of 217 mV at 10 mA cm^(-2)and 263 m V at 100 m A cm^(-2)in 1.0 M KOH.Noteworthy,the Fe-NiO_(x)(OH)_(y)/NF also demonstrates high stability in 30 wt.%KOH.This strategy of regulating the electrochemical reconstruction process sheds light on the construction of stable and efficient OER catalysts for industrial water electrolysis.