A Brown Mesoporous TiO2‐x/MCF Composite with an Extremely High Quantum Yield of Solar Energy Photocatalysis for H2 Evolution

A brown mesoporous TiO 2‐x /MCF composite with a high fluorine dopant concentration (8.01 at%) is synthesized by a vacuum activation method. It exhibits an excellent solar absorption and a record‐breaking quantum yield (Φ = 46%) and a high photon–hydrogen energy conversion efficiency (η = 34%,) for solar photocatalytic H 2 production, which are all higher than that of the black hydrogen‐doped TiO 2 (Φ = 35%, η = 24%). The MCFs serve to improve the adsorption of F atoms onto the TiO 2 /MCF composite surface, which after the formation of oxygen vacancies by vacuum activation, facilitate the abundant substitution of these vacancies with F atoms. The decrease of recombination sites induced by high‐concentration F doping and the synergistic effect between lattice Ti 3+ –F and surface Ti 3+ –F are responsible for the enhanced lifetime of electrons, the observed excellent absorption of solar light, and the photocatalytic production of H 2 for these catalysts. The as‐prepared F‐doped composite is an ideal solar light‐driven photocatalyst with great potential for applications ranging from the remediation of environmental pollution to the harnessing of solar energy for H 2 production.