One stone, three birds strategy for synthesis of N-doped activated carbon-supported surface-enriched and redispersed Pd NPs via plasma for formic acid dehydrogenation

Abstract

Rational design of supported Pd catalysts with excellent performance for H2 production via inexpensive and sustainable formic acid (FA) dehydrogenation remains challenging. N-doped activated carbon (AC)-supported surface-enriched and redispersed Pd nanoparticles (Pd/ACCP (250 W, 10 min)) with enhanced performance for FA dehydrogenation were prepared via plasma-assisted thermal reduction (input power: 250 W, discharge time: 10 min). The TOFinitial (initial turnover frequency) of Pd/ACCP (250 W, 10 min) reached 1276 h−1, and gas generation over it for the first and third reaction cycles was 1.11 and 1.52 times higher, respectively, than that of Pd/ACC and 1.25 and 12.40 times higher, respectively, than that of Pd/AC (Sigma–Aldrich). Characterization results indicated that Pd/ACCP (250 W, 10 min) had surface-enriched and redispersed Pd species, owing to the plasma etching and strong electric field, large specific surface area, small Pd particle size, and high Pd/C atomic ratio. Enhanced N doping of AC was achieved via plasma treatment, and N mainly existed as highly active pyridine nitrogen. The plasma-based strategy yielded Pd/ACCP (250 W, 10 min) with excellent catalytic performance for FA dehydrogenation. This study provides insights into plasma-controllable synthesis of supported metal catalysts and delivers a new rational design concept of FA dehydrogenation catalysts.