A BiVO 4 /Fe 2 O 3 heterojunction for non-enzymatic photoelectrochemical (PEC) determination of hydrogen sulfide (H 2 S) is reported. The BiVO 4 /Fe 2 O 3 heterojunction promoted the separation of photo-generated carriers, reduced electron-hole recombination, and thus improved electron collection and photocurrent. The proposed BiVO 4 /Fe 2 O 3 /FTO sensor exhibited a linear range of 1-500 μM and a detection limit of 0.51 nM H 2 S. In addition, high selectivity, good reproducibility, and stability were obtained for H 2 S sensing. The detection of H 2 S in water and serum samples demonstrated its feasibility. This work provides a new strategy to detect and understand the bio-function of H 2 S in the biological environment.