Highly Dispersed Ni on Nitrogen-Doped Carbon for Stable and Selective Hydrogen Generation from Gaseous Formic Acid

Ni supported on N-doped carbon is rarely studied in traditional catalytic reactions. To fill this gap, we compared the structure of 1 and 6 wt% Ni species on porous N-free and N-doped carbon and their efficiency in hydrogen generation from gaseous formic acid. On the N-free carbon support, Ni formed nanoparticles with a mean size of 3.2 nm. N-doped carbon support contained Ni single-atoms stabilized by four pyridinic N atoms (N-4-site) and sub-nanosized Ni clusters. Density functional theory calculations confirmed the clustering of Ni when the N-4-sites were fully occupied. Kinetic studies revealed the same specific Ni mass-based reaction rate for single-atoms and clusters. The N-doped catalyst with 6 wt% of Ni showed higher selectivity in hydrogen production and did not lose activity as compared to the N-free 6 wt% Ni catalyst. The presented results can be used to develop stable Ni catalysts supported on N-doped carbon for various reactions.

Automated summary

Ni supported on N-doped carbon was studied for its application in traditional catalytic reactions. The structure of 1% and 6% Ni catalysts on N-free and N-doped carbon supports were compared, along with their efficiency in hydrogen generation from gaseous formic acid. It was found that N-doped carbon supported stable Ni single-atoms and sub-nanosized Ni clusters. The results showed that both Ni single-atoms and clusters had similar reaction rates, and the 6% Ni catalyst on N-doped carbon exhibited higher selectivity and comparable activity in hydrogen production.