*2.1. Materials*

Following reagents were used: BiCl3, ethanolamine and acetaminophen (Aladdin Biochemical Technology Co., Ltd., Shanghai, China), Graphite powder and NH4VO3 (Bodi Chemical Co., Ltd., Tianjin, China), Bi(NO3)3·5H2O and ethylene diamine tetraacetic acid disodium salt (EDTA-2Na) (Tianjin Damao Chemical Reagent Co. Inc., Tianjin, China), formic acid, isopropanol (IPA) and p-Benzoquinone (Sinopharm Chemical Reagents Co., Ltd., Shanghai, China). All chemicals were used as received without further purification. Deionized water was used throughout the experiment.

#### *2.2. Synthesis of BiVO4*/*RGO Composites*

Graphene oxide (GO) was prepared using a modified Hummers' method published in our previous work [20]. BiVO4 nanosheets/RGO composites and BiVO4 nanotubes/RGO composites were synthesized by the hydrothermal method, modified from previously reports [21]. Typically, 158 mg of BiCl3 powder and 59 mg of NH4VO3 powder were added in 50 mL deionized water and stirred for 30 min to produce a homogenous suspension. Then, certain amount of 1 M ethanolamine (0.3 mL for BiVO4 nanosheets; 2.5 mL for nanotubes) was added dropwise. After that, 6.32 mL 1 g L−<sup>1</sup> GO solution was gradually added into the solution and then sonicated for 30 min to make the mixture uniform. The above solution was poured into a 100 mL Teflon-lined autoclave and reacted at 160 ◦C for 12 h. After cooling to room temperature, the resulting yellow precipitates in the reactor are collected and washed several times with alcohol and deionized water. Finally, the as prepared catalysts were dried at 60 ◦C for several hours. BiVO4 nanosheets and BiVO4 nanotubes were synthesized by a similar method without GO addition.

BiVO4 nanoparticles was prepared by a modified method according to the literature [22]. The BiVO4 nanoparticles/RGO composites were prepared by a hydrothermal method. The details are described in the Supplementary Materials.
