Surface-mediated chemical dissolution of two-dimensional nanomaterials toward hole creation

Chemically engineered holes on two-dimensional (2D) nanomaterials may significantly increase the number of edge sites to tune their intrinsic properties to achieve promising performance. Here, we report a general and mild approach to the convenient creation of holes on atomically thin nanosheets for engineering bandgaps and enhancing properties of 2D materials. Through surface blocking, controlled dissolution, and chemical stabilization, WO₃ nanosheets are readily treated to create holes in the presence of bovine serum albumin (BSA) via the reaction of WO₃ with OH^- ions at pH 8. Arising from the increased bandgaps and more edge sites as demonstrated experimentally and theoretically, the resulting holey WO₃ nanosheets exhibit enhanced photocurrents and much better performance during selective adsorption and photocatalytic degradation compared with those of bulky WO₃ and nonporous nanosheets. Also, this approach is further extended to the convenient creation of holes on more 2D nanomaterials such as MoS₂ and C₃N₄ nanosheets, which are facilely made in aqueous solutions of diluted H₂O₂ and HCl, respectively. Overall, this work not only demonstrates a surface-mediated chemical dissolution strategy for generating holes on various ultrathin nanosheets but also provides new opportunities to exploit exotic properties and novel applications of geometrically constructed 2D nanomaterials.