As such, we have attempted to cast a panoramic review of graphene-based photocatalysis, which has covered a systematic understanding of the multifarious roles of graphene in boosting the photocatalytic performance, the key factors affecting the activity of graphene-based composites, some pioneering efforts on investigating the charge carrier dynamics in the graphene-based composites, the photostability of graphene during the photocatalytic processes, comparison of graphene-based and other carbon allotropes-based composite photocatalysts, all the types of reported photoredox processes over graphene-based composite photocatalysts, the current status and opportunities in this active field, and a perspective on how graphene-based composites can be applied to practical applications in solar energy conversion.

To fabricate smart graphene-based composite photocatalysts, it is necessary and still challenging to rationally design graphene-based composites from a system-level engineering consideration, which in analogy to biological systems in nature requires a collective integration of the individual components, interface composition, and fine control of material structure and morphology at the nanoscale. In particular, interface engineering by the combination of tailored individual components that afford special interfacial interaction (e.g., band alignment) such as p–n junctions, heterojunctions, and Z-scheme systems would be an effective strategy for improving the photoactivity of graphene-based composites because it predominantly determines the microscopic transfer pathway of charge carriers, the efficiency of the separation and transfer of charge carriers, and thus the photoactivity. In this regard, the joint effort between experiment and theory on the fundamental in-depth understanding of the charge carrier dynamics over the graphene-based composite photocatalysts would be instructive for designing spatially multicomponent composite architectures, thereby enabling more sophisticated and efficient photocatalytic systems. Regarding the overall photocatalytic performance of graphene-based composites, it is not the issue of only the electrical conductivity of graphene, but the harmonious combination of the structure and morphology of each component and the connection or interaction manner between them in the whole composite.

Further to the above design concept, with regard to the implementation of “potential” of graphene-based composite photocatalysts into “practical” applications, both the construction of sunlight highly reactive fixed graphene-based composite photocatalysts and the design of solar light operating reactors must be taken into account. All of these fundamental and technological issues should essentially be integrated from a system-level consideration, which together determine the overall practical performance of graphene-based photocatalytic systems. In fact, this whole scenario cogitation is of vital importance for any photocatalyst materials to develop their widespread practical applications in artificial photocatalysis. In this sense, the sufficient delivery of potential of graphene-based composite photocatalysts for practical applications requires the joint efforts of both chemists and industrial engineers, instead of subjectively imposing hype on the miracle of graphene. However, considering the trajectory of any material research, it typically takes 20 years or more to emerge from a fundamental understanding to practical applications. Therefore, to be optimistic but rational, the construction of graphene-based composites as the next-generation of photocatalytic systems would take a much longer time than people think.

Looking to the future, there is a wide scope of opportunity and challenge simultaneously existing for this hot research topic. We wish that this review would make the following overarching directions for the next decade of research on graphene-based photocatalysis: (1) the field needs to timely communicate the status, opportunities, and challenges at all levels of research and industry communities, particularly for the newcomers and those who are not intimately involved in graphene-related research, which avoids the exaggerated hype on graphene-promoted photocatalysis; and (2) while it is well recognized that graphene-based composites are feasible for boosting photocatalysis, more attention should be paid to the design of graphene-based composites by a system-level method and, particularly, to an in-depth fundamental understanding of the pathway and dynamics of charge carrier transfer associated with such composites by the joint cooperation between experiment and theory. It is hoped that this review would contribute to advancing the achievement of these goals and shaping the development road of graphene-based composites photocatalysis in the posthype era.

http://pubs.acs.org/doi/abs/10.1021/acs.chemrev.5b00267

中文报道（石墨烯基复合光催化材料的研究进展）：http://www.x-mol.com/news/1744