Fabrication of Co-Grafted\ng‑C<sub>3</sub>N<sub>4</sub>/CdSe-NiO Photocathode for Hydrogen\nEvolution under Visible\nLight

A photocathode for driving water splitting under visible\nlight\nwas constructed using mesoporous nickel oxide as a substrate, two-dimensional\ng-C<sub>3</sub>N<sub>4</sub> nanosheet/zero-dimensional CdSe quantum\ndots as a composite photocatalyst, and cobalt oxime catalyst as an\neconomical cocatalyst. The Co-<i>g</i>-C<sub>3</sub>N<sub>4</sub>/CdSe-NiO cathode displayed a high photocatalytic current\ndensity of −56 μA cm<sup>–2</sup> at a bias of\n−0.1 V vs NHE in the absence of electron sacrifice, which was\nabout 4 times greater than that of the photocathode using only CdSe\nquantum dots (−15 μA cm<sup>–2</sup>) as the photosensitizer.\nSimultaneously, the Faraday efficiency of the photocathode was about\n90.7%.