“…Steady and apparent progress has been seen in the synthesis of its 0-, 1-, 2-, and 3-dimensional nanomaterials and surface facet-selective nano/microstructures as well as in the understanding of its structural, mechanical, thermodynamic, optical, electronic, surface, and interfacial properties. 9,13,14,59 However, its white color and large band-gap limit its practical applications in photocatalytic hydrogen generation, CO 2 reduction, and environmental pollution removal. 57,60−69 Great effort has been devoted to tuning TiO 2 's electronic and optical properties from a variety of angles in order to reach a high photoactivity during the last few decades.…”