The photocatalytic hydrogen evolution based on 3-mercaptopropionic acid stabilized CdS, CdTe, and CdTe0.5S0.5 alloyed quantum dots (QDs) have been investigated under visible-light irradiation in the aqueous solution by using ascorbic acid solution as a sacrificial electron donor and CoCl2·6H2O as a co-catalyst. CdS and CdTeS alloyed QDs exhibits higher hydrogen evolution rates of 9.3 mmol g−1 h−1 and 8 mmol g−1 h−1, respectively, which is about two fold higher than CdTe.