Pd Catalysts Based on C3N4-Modified Activated Carbon Derived from Biomass Residues for the Dehydrogenation of Formic Acid

Formic acid has recently been considered one of the most promising liquid organic hydrogen carriers (LOHCs). Its decomposition to obtain H2 has been fruitfully investigated during recent years using catalysts of a very diverse nature. Most of these catalysts lack stability, so finding stable materials under reaction conditions is highly desirable but challenging. In the present study, catalysts based on Pd nanoparticles supported on C3N4-modified activated carbon derived from biomass residues were developed, characterized, and assessed in the decomposition of formic acid in the liquid phase. These catalysts were prepared using a straightforward method that allowed different nitrogen contents to be achieved in the support and avoided the ex situ reduction in the Pd precursor. The results of the catalytic tests indicated the positive role of incorporating C3N4, leading to catalysts that displayed much better performance than the C3N4-free counterpart. The incorporation of C3N4 resulted in catalysts with small and well-distributed Pd nanoparticles, leaching resistance and modified electronic properties of the Pd species. As a result, promising catalytic activity was observed in the developed materials. Pd/AC_C3N4(19) attained an initial TOF of 2893 h−1, and it preserved most of its catalytic activity for at least six consecutive reaction cycles, which is a remarkable characteristic of the developed catalytic system.