Zinc phthalocyanine/carbon nitride nanosheets photoelectrocatalysts were obtained by evaporation and calcination of the mixture of ZnPc and carbon nitride. It exhibits highly efficient synergistic function between PC-CO2RR and EC-CO2RR. The energy band matching between the ZnPc and carbon nitride results in the faster electrons transfer and less electron-hole pairs recombination. The optimized ZnPc/carbon nitride at a ratio of 0.1 wt% demonstrates high efficiency in photoelectrocalytic reduction of CO2 under visible light, generating a major product of methanol at a yield of 13 mu mol.cm(-2) after 8 h. The efficiency of photoelectrocalytic reduction of CO2 to methanol is 2.6 times as high as that of electrocatalytic CO2 reduction reaction, and 5.9 times as high as that of photocatalytic CO2 reduction reaction. The mechanism of the photoelectrocatalytic CO2 reduction reaction to methanol was discussed in detail. (C) 2019 Elsevier Inc. All rights reserved.