Dimensional heterojunction design: The rising star of 2D bismuth-based nanostructured photocatalysts for solar-to-chemical conversion

With the fast-pace digitalization evolution in the current generation's lifestyle and the industry revolution, the energy demand has been skyrocketed. Recently, the two-dimensional (2D) bismuth-based nanomaterials emerged as a promising photocatalyst candidate in solar fuel conversion, not only for its exceptional light absorption capability and tunable optical properties, but it also can be synthesized into diverse variety of nanomaterials with different ranges of potential gap and band position to fulfill the potential requirement of wide range of photocatalytic reaction. Yet, the weak light harvesting ability and ultrafast charge recombination has restricted its potential in commercial application. Thus, recent researches have been focusing on tackling these issues by incorporating some modification strategies such as heteroatom doping, vacancy engineering, facet engineering, bismuth rich strategy and heterojunction engineering. Herein, this review article presents the state-of-the-art modifications on 2D bismuth-based parent material, specifically on the relationship between each of the modification strategy on the electronic properties and surface chemistry in achieving boosted photocatalytic performance. In the view of the unique charge interaction between two semiconductors with different dimensions, we systematically discuss the rational heterostructure design from the dimensionality perspective, namely, point-to-face, line-to-face, face-to-face, and bulk-to-face in solar fuel conversion to provide inspiring insights for future interface engineering. Finally, the challenges and the future research outlook in the solar-to-fuel conversion are highlighted to push forward the design of high-performance bismuth-based photocatalyst in realizing commercial-scale solar-to-fuel conversion.