Effective visible-light catalysis triggered by the orbital coupling and carrier transfer in α-phase phthalocyanine/graphene oxide van der Waals heterostructure

[Display omitted] •The energy degeneration occurs between π orbital of α-H2Pc and valence band of GO in the vdWH.•The Fermi level of the system is thus engineered, and the carriers are effectively separated.•The effective photo-oxidation of As(III) is realized without electron/hole sacrifices or degassing.•Pc-GO suggests an excellent photocatalytic activity in the range of the visible light. The application of graphene oxide (GO) in the photoelectronic materials are greatly restricted by the ineffective carrier separation and mobility, as well as the poor utilization of visible light. In this study, a strategy is proposed to overcome these disadvantages via the fabrication of van der Waals heterostructure. The target heterostructure, Pc-GO, is prepared by the simple assembly of α-phase phthalocyanine (α-H2Pc) and GO in water. The energy degeneration is observed between π orbital of α-H2Pc and valence band of GO, which acts as the channel for transferring the photogenerated electrons from H2Pc to GO. Interestingly, electron transfer becomes more remarkable with the decreasing H2Pc layers. The Fermi level of the heterostructure is thus engineered. Fast mobility of carriers is also demonstrated by the spectroscopic technologies and electrochemical methods. Based on these advantages, the effective photocatalytic detoxication of As(III) is realized by Pc-GO without any electrons/holes sacrifices or additional degassing, and the average reaction rate is 0.68 mg g-1h−1. Especially, Pc-GO suggests an excellent photocatalytic activitty in the range of visible light, and 53.1% of the activity is maintained in contrast to that under the full spectrum. Pc-GO even remains 22 % of photocatalytic property after wrapped by a A4 printing paper, which is essential for the practical application of Pc-GO in natural muddy water. Moreover, the visible-light catalysis of Pc-GO is demonstrated to correlate with the unique α-H2Pc stacks. This work extends the preparation strategies of As(III) remediation materials, and promises a possible method to engineer the photoelectric properties of the device via changing the arrangement of two-dimensional semiconductor.