Anchoring PdAg nanoparticles on ZIF-67-derived Co@NC composite as a catalyst for efficient hydrogen evolution from formic acid

A facile wet-chemical method was utilized to graft the PdxAg1-x alloy nanoparticles on the Co@NC composites derived from ZIF-67 by carbonization at different temperatures. The characterization results verified that the carbonization temperature exhibits a marked influence on the physical properties of the Co@NC composites. The surface area increased with temperature, ensuring the high dispersion of the PdAg alloy nanoparticles on the surface of the Co@NC composites. The performance evaluation of the dehydrogenation reaction of formic acid showed that the PdAg alloy nanoparticles deposited on Co@NC obtained at a carbonization temperature of 900 °C exhibited the highest activity. The catalytic performance of PdAg/Co@NC catalysts towards H2 generation was strongly related to the composition of the PdAg alloy and followed the trend of Pd2Ag1/Co@NC > Pd1Ag1/Co@NC > Pd9Ag1/Co@NC > Pd/Co@NC > Pd1Ag2/Co@NC. The residual metallic Co in the carbon matrix is somewhat beneficial to improving the catalytic activity and stability of the catalyst.