Amino-functionalized nitrogen-doped carbon catalysts derived from bio-tar: Synergistic regulation of acid-base sites for highly efficient glucose-to-lactic acid conversion

Efficiently converting biomass-derived glucose to lactic acid (LA) is crucial for biomass valorization and the replacement of petroleum-based chemicals. However, traditional catalytic systems depend on non-renewable feedstocks and poorly regulate acid-base sites, leading to severe side reactions that limit LA yield. Here, we present a rationally designed nitrogen-doped carbon-based catalyst derived from bio-tar, aimed at addressing these issues and optimizing its catalytic performance for glucose conversion to LA. In this catalyst system, nitrogen doping selectively introduces basic sites, such as pyridinic N and pyrrolic N, on the carbon support. Ammonium grafting modification further adjusts the acid-base site ratio, achieving optimal balance at 15 % Zn loading, which significantly suppresses side reactions. Amino functionalization effectively regulates the density of surface acid-base sites. Introducing a Na₂CO₃/NaHCO₃ buffer system inhibits LA auto-oxidation and achieves a high LA yield of 79.64 % at 180 °C for 8 h. Stability tests indicate that the LA yield obtained with the amino-functionalized catalyst remains above 92 % after five reaction cycles. This study innovatively combines bio-tar valorization with active site regulation, providing a green and efficient catalyst design strategy through the synergistic effects of “nitrogen doping, acid-base site optimization, and buffer system.” This offers a new approach for the sustainable conversion of carbohydrates.