Heterostructured Co/CePO4 electro-/photocatalyst for efficient electro-/photocatalytic hydrogen evolution

Developing a high-efficiency, stable and inexpensive bifunctional electrocatalyst/photocatalyst for hydrogen evolution reaction (HER) with suitable Gibbs free energy of hydrogen and rich electron transport channels remains a significant challenge. Herein, noble-metal-free Co nanoparticles decorated CePO4 nanowires Co/CePO4 were synthesized using Co-BTC/CePO4 as a precursor via hydrothermal and calcination methods. A robust coupling heterostructure interface can be generated through carefully designed routes between Co nanoparticles and CePO4 nanowires. In the HER process, the heterostructure interface can promote the composite catalysts conductivity, increase the active sites, charge-transfer efficiency, and adjust the desorption energy of hydrogen, thus enhancing their HER activity. Benefited from its specific structure, the obtained Co/0.1CePO4 catalyst exhibits splendid electrocatalytic HER performance with an overpotential of only -108 mV at -10 mA cm-2 and a low Tafel slope of 85 mV decade-1, which is superior to many reported noble-metal-free catalysts. Especially, Co/0.1CePO4 catalysts show an overpotential close to commercial 20 wt% Pt/C (-377mV vs -340 mV) at a high current density of -200 mA cm-2. Co/0.1CePO4 catalyst also exhibits excellent photocatalytic hydrogen production rate (~87.5 umol h-1) when working with organic photosensitizer Eosin Y. Furthermore, the Co/0.1CePO4 catalyst reveals favorable stability in both electrocatalytic and photocatalytic HER. This research provides a new insight for fabricate efficient and stable composite HER catalysts.