Rational Construction of 2D/3D Co3O4/NH2‐MIL‐53(Al) Heterostructures to Facilitate Photocatalytic Hydrogen Evolution

Based on the principle of strengthening photogenerated carrier separation and interfacial charge transfer, the heterojunction structure is constructed to improve the performance of photocatalytic hydrogen evolution. For this reason, a 3D gear‐like NH 2 ‐MIL‐53(Al) material is synthesized by the template‐free hydrothermal method, and then the 2D irregular loose flake material Co 3 O 4 derived from metal–organic framework is loaded. The hydrogen evolution rate of the composite photocatalyst Co 3 O 4 /NH 2 ‐MIL‐53 (Al) is much greater than that of two single catalysts after progressively improving the experimental conditions. First of all, this is attributed to the heterojunction structure formed by the appropriate arrangement of energy bands. Second, the rationality of the heterojunction structure is confirmed by the change of binding energy of atoms in in situ irradiation X‐ray photoelectron spectroscopy and the calculation results of density functional theory. Further testing of the materials’ photoelectrochemical properties reveals that the composite photocatalyst Co 3 O 4 /NH 2 ‐MIL‐53 (Al) has improved light adsorption, a lower overpotential, and a smaller Tafel slope. These results show that the hybrid material Co 3 O 4 /NH 2 ‐MIL‐53 (Al) improves the charge separation activity and hydrogen evolution reaction kinetics, thus enhancing the photocatalytic performance.