Here, we discuss recent efforts during the last 5 years for the development of molecular electrocatalysts involving metal hydride intermediates with particular attention to iron carbonyl clusters. This review begins with a brief description of thermodynamic properties (hydricity) of metal hydride intermediates and methods of hydricity measurements, specifically for iron carbonyl clusters. We then discuss two important reactions by iron carbonyl clusters relevant to solar fuel catalysis: electrocatalytic reduction of CO2 to formate and proton reduction to hydrogen. These examples are included because they provide valuable mechanistic insights into the design of catalysts that produce hydrogenated products selectively from CO2.