Three-dimensional alumina-supported hafnium phosphide as an efficient and robust catalyst for the conversion of glucose into 5-hydroxymethylfurfural

Glucose valorization is a promising approach for achieving high-value utilization of biomass, with its catalytic conversion to 5-hydroxymethylfurfural receiving considerable attention. However, developing an efficient and robust heterogeneous catalyst for the process remains challenging. Herein, we demonstrate a feasible strategy that combines the in-situ growth of a hafnium phosphide (HfP) active phase with the anchoring capability of a three-dimensional alumina support (F 3D -Al 2 O 3 ) to achieve catalyst availability. Various characterization techniques confirmed that the constructed HfP/F 3D -Al 2 O 3 catalyst possesses a well-developed three-dimensional flower-like hierarchical porous structure, which fully exposes the acidic sites and enhances mass transfer, thus outperforming two-dimensional sheet-like and one-dimensional bulk catalysts. Under optimal reaction conditions, the HfP/F 3D -Al 2 O 3 catalyst drove the conversion of glucose into the desired HMF with a yield of 70%. Benefiting from the interaction between the support Al 3+ center (Al V ) and the HfP active phase, the HfP/F 3D -Al 2 O 3 catalyst remained effective even after ten consecutive cycles. Furthermore, the pathway for the conversion of glucose into HMF catalyzed by HfP/F 3D -Al 2 O 3 was also monitored, revealing that it proceeds through the isomerization of glucose via a 1, 2-enediol intermediate followed by dehydration of fructose. Therefore, the glucose conversion pathway presented in this study has the potential to provide valuable insights for bioenergy refining technologies.