'Black' TiO -in the widest sense, TiO reduced by various treatments-has attracted tremendous scientific interest in recent years because of some outstanding properties; most remarkably in photocatalysis. While the material effects visible light absorption (the blacker, the better), black titania produced by high pressure hydrogenation was recently reported to show another highly interesting feature; noble-metal-free photocatalytic H generation. In a systematic investigation of high-temperature hydrogen treatments of anatase nanoparticles, TEM, XRD, EPR, XPS, and photoelectrochemistry are used to characterize different degrees of surface hydrogenation, surface termination, electrical conductivity, and structural defects in the differently treated materials. The materials' intrinsic activity for photocatalytic hydrogen evolution is coupled neither with their visible light absorption behavior nor the formation of amorphous material, but rather must be ascribed to optimized and specific defect formation (gray is better than black). This finding is further confirmed by using a mesoporous anatase matrix as a hydrogenation precursor, which, after conversion to the gray state, even further enhances the overall photocatalytic hydrogen evolution activity.

Herein, recent progress in the field of tin oxide (SnO2)‐based nanosized and nanostructured materials as conversion and alloying/dealloying‐type anodes in lithium‐ion batteries and beyond (sodium‐ and potassium‐ion batteries) is briefly discussed. The first section addresses the importance of the initial SnO2 micro‐ and nanostructure on the conversion and alloying/dealloying reaction upon lithiation and its impact on the microstructure and cyclability of the anodes. A further section is dedicated to recent advances in the fabrication of diverse 0D to 3D nanostructures to overcome stability issues induced by large volume changes during cycling. Additionally, the role of doping on conductivity and synergistic effects of redox‐active and ‐inactive dopants on the reversible lithium‐storage capacity and rate capability are discussed. Furthermore, the synthesis and electrochemical properties of nanostructured SnO2/C composites are reviewed. The broad research spectrum of SnO2 anode materials is finally reflected in a brief overview of recent work published on Na‐ and K‐ion batteries.