A formic acid decomposition catalyst system includes organometallic complexes having formula 1: wherein: M is a transition metal; E is P, N, or C (as in imidazolium carbene); R1, R2 are independently C1-6 alkyl groups; o is 1, 2, 3, or 4; R3 are independently hydrogen, C1-6 alkyl groups, OR14, NO2, halogen; R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R15, R16 are independently hydrogen or C1-6 alkyl groups; R14 is a C1-6 alkyl group; and X− is a negatively charge counter ion.