Selective electrochemical hydrogenation of furfural to 2-methylfuran over a single atom Cu catalyst under mild pH conditions†

Furfural is regarded as one of the most promising bio-based feedstocks in the bio-refinery industry. Selective hydrogenation of the carbonyl bond in furfural plays a vital role in its conversion to downstream products. Electrochemical hydrogenation (ECH) method provides a green and sustainable way for this reaction. Yet, it still suffers from harsh pH conditions and low selectivity for highly reduced products, such as 2-methylfuran. In this study, high faradaic efficiencies of over 90% for furfuryl alcohol and 60% for 2-methylfuran were obtained in a near-neutral environment (pH = 5) at -0.75 V and -0.90 V vs. the reversible hydrogen electrode, respectively. The key to this success is the integration of single atom copper active sites and the oxophilic phosphorus dopants in a single catalyst. Single atom Cu sites are found to be the active centers for this reaction and decreasing the size of Cu sites to a single atom enhances the efficiencies of the ECH reactions by suppressing the competing hydrogen evolution reaction. Phosphorus doping facilitates furfural hydrogenation to 2-methylfuran via a sequential two-step reduction process. This study opens up possibilities for the selective electrochemical hydrogenation of furfural to 2-methylfuran under mild conditions.

Automated summary

In this study, high faradaic efficiencies for furfuryl alcohol and 2-methylfuran were achieved in near-neutral conditions through the integration of single atom copper active sites and phosphorus dopants in a single catalyst. Single atom Cu sites were identified as the active centers for the reaction, leading to enhanced efficiencies by suppressing the competing hydrogen evolution reaction. Phosphorus doping facilitated furfural hydrogenation to 2-methylfuran via a sequential two-step reduction process, opening up possibilities for selective electrochemical hydrogenation under mild conditions.