CoP nanotubes formed by Kirkendall effect as efficient hydrogen evolution reaction electrocatalysts

CoP nanotubes are synthesized through a nanoscale Kirkendall effect using Co(CO3)(0.35)Cl-0.2(OH)(1.10) nanorods as the cobalt source and template. CoP nanotubes and nanorods can be selectively synthesized by controlling the Co and P molar ratio in the phosphidation process, further confirming the diffusion controlled Kirkendall effect. Benefiting from the high surface area and improved mass and charge transportation, the CoP nanotubes exhibit higher hydrogen evolution catalytic activity than that of CoP nanorods and nanoparticles. The CoP nanotubes have a small onset potential of 55 mV for hydrogen evolution reaction, and high durability indicating by that the catalytic activity almost no change after 2000 cyclic voltammetry cycles. (C) 2017 Published by Elsevier B.V.