Synthesis and Properties of Organotrialkoxysilane Functionalized Palladium-Cobalt Heterogeneous Catalysts for Oxygen Evolution Reaction

Despite the widespread use of noble metal nanocatalysts in heterogeneous catalysis, their catalytic efficiency per-noble metal atom is still inadequate. Organotrialkoxysilane mediated formation of Co@Pdnps were made using Co-NTA nanowires as a precursor. Co@Pdnps were synthesized using variable content of organotrialkoxysilane in an N-doped carbon matrix (Co@Pdnps) to control the presence of nanostructured silica after calcination useful in OER and analyzed by XRD, TEM, SEM, XPS, and EDX. Three systems of bimetallic nanocatalysts of composition after calcination: (i) Co@Pdnps1: Si = 4.54%; Pd = 4.36% and Co = 91.10%; (ii) Co@Pdnps2: Si = 2.81%; Pd = 5.83% and Co = 91.36% and (iii) Co@Pdnps3: Si = 0.00, Pd = 9.48, Co = 90.52 are made justifying the impact of nanostructured silica and palladium nano geometry on OER. The presence of nanostructured silica facilitates (a) re-cyclability of nanocatalyst, (ii) significantly improves the palladium nano geometry, (iii) effective interaction of cobalt and palladium components during OER. A nanostructured silica-derived thin film composed of Co@Pdnps produced a very high current density at a low overpotential with a minor Tafel slope of 39 mV dec(-1) and a catalyst loading of 3.5 mg cm(-2) on the carbon cloth. In the absence of silica, the nanocatalysts are relatively larger with comparatively less current density(19 mA cm(-2)) as compared to (20.5 mA cm(-2)) recorded with high silica content.