Hydride transfer (HT) is ubiquitous in catalytic reduction reactions. In heterogeneous electrocatalysis, the hydride donor could be a molecular catalytic intermediate adsorbed on an electrode surface. The stability and hydride-donating capability of such an intermediate may determine overall catalytic efficiency. Here, we report how to fine-tune a hydride donor's performance via doping an electrode surface. For semiconductor electrodes, we find that the ionization energy of the surface dopant can serve as a good descriptor for both the stability and hydride-donating capability of the catalytic intermediate adsorbed on the doped site. For the specific case of CO2 reduction on p-GaP, where adsorbed 2-pyridinide (2-PyH-*) was predicted to be the most likely hydride-donating species, we predict that its catalytic performance should be particularly enhanced by substituting Ga with Ti on the electrode surface; Sc, Al, and V surface dopants also could be worthy of further investigation.