Template-Free One-Pot Synthesis of Ni-Beta Zeolites: Protonation Modulation for Boosted Methanol Electrooxidation

Developing high-performance non-precious metal catalysts for the methanol oxidation reaction remains a challenge for direct methanol fuel cells. Herein, a nickel-doped Beta (Ni-Beta) zeolite was successfully synthesized via a template-free one-pot hydrothermal route followed by protonation via ammonium exchange. In this work, the protonation process strengthened metal–support interaction to form Ni2+/Ni3+ redox pairs, introduced abundant acidic sites, and optimized the zeolitic pore structure. Optimized Ni-H-Beta-170 (Si/Ni = 170) achieved a remarkable mass activity of 71.6 A g−1 at 0.66 V vs. Hg/HgO, around 10-fold higher than unprotonated Ni-Beta zeolite. The improved activity originates from reversible Ni2+/Ni3+ cycles for eliminating toxic COads, enriched acid sites accelerating C–H cleavage of methanol and formation of active NiOOH, and enlarged pore volume facilitating mass transfer. This work offers a low-cost strategy toward advanced non-precious methanol oxidation reaction electrocatalysts.