Enhanced hydrogen evolution performance by 3D ordered macroporous Ru-CoP@NC electrocatalysts

Electrocatalytic water splitting coupled with sustainable energies is identified as an environmentally friendly and renewable strategy to generate high-quality hydrogen for the fuel cells.However,the main challenge is to develop high performance,low cost and chemically stable electrocatalysts to decline the energy barriers and enhance the sluggish kinetics of hydrogen evolution reaction(HER).Herein,a three-dimensional hierarchically ordered macroporous Ru-CoP@NC electrocatalyst(3DOM Ru-CoP@NC)derived from ordered macro-microporous metal-organic frameworks has been prepared using the precursor@template and double-solvent methods.The prepared 3DOM Ru-CoP@NC catalyst exhibits an overpotential of 15 mV(j=10 mA·cm^(-2))and a reaction Tafel slope of 38 mV·dec^(-1)in alkaline electrolyte,which are superior to commercial Pt@C catalyst.Additionally,the overpotential and reaction Tafel slope of this catalyst in acidic media are 45 mV and 50 mV·dec^(-1),respectively.The outstanding HER activities of 3DOM Ru-CoP@NC catalysts are ascribed to the 3D highly interconnectedreticular nanospaces that can increase effective reaction active sites.The N dope d carbon framework improves the electronic properties and conductivity.Moreover,the strong interaction of Ru and CoP nanoparticles also boosts the HER process.These results indicate that 3DOM Ru-CoP@NC catalysts with high catalytic activities have a broad application prospect in the future.

Optimizing hydrogen ad/desorption of Mg-based hydrides for energy-storage applications

Hydrogen energy is expected to be an“ideal fuel”in the era of decarbonization.The discovery,de-velopment,and modification of high-performance hydrogen storage materials are the keys to the fu-ture development of solid-state hydrogen storage and hydrogen energy utilization.Magnesium hydride(MgH_(2)),with its high hydrogen storage capacity,abundant natural reserves,and environmental friend-liness,has been extensively researched.Herein,we briefly summarize the typical structure and hy-drogenation/dehydrogenation reaction mechanism of MgH_(2)and provide a comprehensive overview of strategies to effectively tune the thermodynamics and kinetics of Mg-based materials,such as alloy-ing,nanosizing,the introduction of additives,and composite modification.With substantial efforts,great achievements have been achieved,such as lower absorption/desorption temperatures and better cy-cling stability.Nonetheless,some pivotal issues remain to be addressed,such as unfavorable hydro-genation/dehydrogenation factors,harsh conditions,slow kinetics,incomplete dehydrogenation,low hy-drogen purity,expensive catalysts,and a lack of valid exploration of mechanisms in the hydrogena-tion/dehydrogenation process.Lastly,some future development prospects of MgH_(2)in energy-efficient conversion and storage have been presented,including advanced manufacturing ways,stabilization of nanostructures,the introduction of additives combined with structural modification,and utilization of advanced characterization techniques.