A hierarchically porous and hygroscopic carbon-based catalyst from natural wood for efficient catalytic reduction of industrial high-concentration 4-nitrophenol

Abstract

4-Nitrophenol (4-NP) with high toxicity and non-biodegradability has been causing a great threat to the environment and human health. Catalytic reduction of high-concentrated 4-NP in wastewater to 4-aminophenol (4-AP) and the subsequent recovery and reuse of catalysts are highly demanded for the practical treatment of industrial pollutants, yet are still limited in low mass transfer efficiency and poor stability of catalysts. Herein, we developed a composite catalyst of Pd nanoparticles (NPs) decorated 3D-activated carbon (Pd/3D-AC) to synergistically catalytic reduce high-concentrated industrial 4-NP (14.38 mM) by using natural wood as a 3D scaffold. The hierarchically porous 3D-AC demonstrates abundant surface-active sites (929 m2·g−1) for adequate and unaggregated anchoring Pd NPs (0.61 %), and the interconnected mass transfer channels and hygroscopic behavior of Pd/3D-AC yield an efficient chemical reaction in solution. As a result, the turnover frequency of the Pd/3D-AC is up to 1.68 min−1, and the synergistic interaction occurs to the 3D-AC and Pd NPs. Even after 10 cycles of catalysis, no deactivation was observed to Pd/3D-AC, demonstrating excellent stability and reusability. Moreover, the Pd/3D-AC catalyst contributes to a high conversion rate to 4-NP, with the yield of obtained 4-AP more than 99.9 % within 10 min. This facile strategy of loading metal nano-catalysts on hierarchically porous wood puts forward a flexible and effective approach for promoting the catalytic performance and the practical treatment of industrial wastewater.