Mesoporous Carbon Shell Encapsulated Co/Co2P Composite for Electrocatalytic Hydrogen Evolution Reaction: The Effect of Cd Initiator on its Catalytic Performance

Herein, a novel cadmium nitrite initiated mesoporous carbon shell encapsulated binary cobalt/cobalt phosphide (Co/Co 2 P@MC-(Cd x )) composites were first prepared by a facile solvothermal reaction following a phosphorization procedure. The Co/Co 2 P@MC-(Cd 0.5 ), with molar ratio of Cd/Co = 0.5 in the initial feeding stock, exhibited overpotentials of as low as 99 mV at 10 mA cm −2 and small Tafel slopes of 53 mV dec −1 under 0.5 M H 2 SO 4 conditions. Various techniques further demonstrated that the superior activity of Co/Co 2 P@MC-(Cd 0.5 ) was attributed to the introduction of Cd initiator, which resulted in the mesoporisity on carbon shell and the modified electron state between the Co and Co 2 P. This novel Cd initiated mesoporous carbon encapsulated Co/Co 2 P composites hold promising potential for utilization in the hydrogen evolution from electrocatalytic water splitting. Graphic Abstract A novel cadmium nitrite initiated mesoporous carbon shell encapsulated binary cobalt/cobalt phosphide (Co/Co 2 P@MC-(Cd x )) composites were first prepared. The Co/Co 2 P@MC-(Cd 0.5 ), with molar ratio of Cd/Co = 0.5 in the initial feeding stock, exhibited overpotentials of as low as 99 mV at 10 mA cm −2 and small Tafel slopes of 53 mV dec −1 under 0.5 M H 2 SO 4 conditions. The superior activity of Co/Co 2 P@MC-(Cd 0.5 ) was attributed to the introduction of Cd initiator, which resulted in the mesoporisity on carbon shell and the modified electron state between the Co and Co 2 P.