Three-dimensionally(3D) ordered mesoporous carbon sphere arrays(OMCS) are explored to support high loading(60 wt%) Pt nanoparticles as electrocatalysts for the methanol oxidation reaction(MOR).The OMCS has a unique hierarchical nanostructure with ordered large mesopores and macropores that can facilitate high dispersion of the Pt nanoparticles and fast mass transport during the reactions. The prepared Pt/OMCS exhibits uniformly dispersed Pt nanoparticles with an average size of ~ 2.0 nm on the mesoporous walls of the carbon spheres. The Pt/OMCS catalyst shows significantly enhanced specific electrochemically active surface area(ECSA)(73.5 m^2g^(-1)) and electrocatalytic activity(0.69 mA cm^(-2))for the MOR compared with the commercial 60 wt% Pt/C catalyst.
Electrochemical water splitting is a facile and effective route to generate pure hydrogen and oxygen.However,the sluggish kinetics of hydrogen evolution reaction(HER) and especially oxygen evolution reaction(OER) hinder the water splitting efficiency.Meanwhile,the high-cost of noble-metal catalysts limit their actual application.It is thus highly urgent to exploit an economical and earthabundant bifunctional HER and OER electrocatalyst to simplify procedure and reduce cost.Herein,we synthesize the three-dimensionally ordered macro-/mesoporous(3 DOM/m) Ni_(x)Co_(100-x) alloys with distinctive structure and large surface area via a dual-templating technique.Among them,the3 DOM/m Ni61Co39 shows the lowest overpotentials of 121 mV and 241 mV at 10 mA/cm^(2) for HER and OER,respectively.Furthermore,when employed for water splitting,the Ni_(61)Co_(39) only requires 1.60 V to approach 10 mA/cm^(2) and presents excellent stability.These encouraging performances of the Ni_(61)Co_(39) render it a promising bifunctional catalyst for overall water splitting.
