Tandem reactions enable the sequential synthesis of value-added chemicals, as exemplified by the conversion of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL) via hydrogenation and subsequent lactonization, with 4-hydroxyvaleric acid (HVA) as the intermediate. However, achieving such tandem electrocatalysis in a single electrolyzer is challenging because the two steps require distinct pH conditions: the former favors neutral or alkaline media, whereas the latter requires a strongly acidic medium. Here we create a pH gradient at the electrode–electrolyte interface by modifying a Pb electrocatalyst with cetyltrimethylammonium bromide (CTAB). The modified electrocatalyst shows >80% GVL selectivity and >50% Faradaic efficiency (FE) over 50–200 mA cm−2. Mechanistic studies show that ordered CTAB arrangements on the Pb surface disrupt the interfacial hydrogen-bond network, lowering the local H+ concentration near the Pb surface while maintaining higher acidity in the bulk electrolyte, thereby facilitating tandem LA-to-GVL conversion. This study demonstrates distinct microenvironment engineering for tandem electrosynthesis in a single electrolyzer. Tandem electrosynthesis is challenging because sequential reaction steps often require incompatible chemical environments. Here, the authors report the creation of pH gradient via microenvironment engineering, enabling levulinic acid to γ-valerolactone conversion in a single electrolyzer.
Ji et al. (Wed,) studied this question.