Constructing S‐scheme charge separation in cobalt phthalocyanine/oxygen‐doped g‐C 3 N 4 heterojunction with enhanced photothermal‐assisted photocatalytic H 2 evolution

Abstract Hydrogen acquisition from solar energy is an effective way to address energy crisis, which makes the development of efficient photocatalysts become the main direction of scientific research. Herein, cobalt phthalocyanine/oxygen‐doped g‐C 3 N 4 (CoPc/OCN) S‐scheme heterojunction photocatalyst was designed by coupling multi‐step calcination with solvothermal method for enhanced photothermal‐assisted photocatalytic H 2 evolution. The multi‐step calcined g‐C 3 N 4 is easier for O‐doping formation, and the ethanol solvothermal strategy is utilized to enhance the dispersion of CoPc on OCN nanosheet surface and forms sufficient S‐scheme heterojunction through H‐bonds. In addition, the active sites and excellent photothermal properties of CoPc itself further improve the integrated photocatalytic activity of CoPc/OCN S‐scheme heterojunction. The optimal photocatalytic hydrogen evolution rate of CoPc/OCN S‐scheme heterojunction photocatalyst reached 9.56 mmol·g −1 ·h −1 , which is 2.69 and 1.23 times higher than that of CN and OCN, respectively. This work provides a valuable design idea and scheme for enhancing the multi‐factor co‐assisted photocatalytic H 2 evolution performance.