Highly selective electrocatalytic hydrogenation of cinnamaldehyde over tin dioxide-supported palladium nanocatalysts

Selective hydrogenation of α, β-unsaturated aldehydes has always been a hot research topic owing to favorable thermodynamics in CC hydrogenation. In this work, a series of Pd/SnO2 nanocatalysts were facilely synthesized under mild conditions, via the reduction of Na2PdCl4 by dimethylaminoborane. Under galvanostatic electrolysis at 3.33 mA cm−2 for 8 h, the selective conversion of cinnamaldehyde (CAL) was achieved over Pd/SnO2-coated carbon fiber in neutral phosphate buffer, giving the cinnamyl alcohol (COL) selectivity of 78.85% at the conversion of 84.88%. The Pd/SnO2 nanocatalysts outperform commercial Pd/C catalysts, showing high COL selectivity and faradaic efficiency. The cathodic reduction potential of CAL over Pd4·3/SnO2 occurs at −0.92 V. The SnO2 support is beneficial to promote the CO adsorption of CAL and lower the HER activity of Pd nanocatalysts, thereby contributing to superior activity of Pd4·3/SnO2 for selective hydrogenation of CAL.