Revealing How Acid Sites Enhance the Electrocatalytic Glycerol Oxidation Performance on Pt Loaded Zeolite-Carbon Composite Materials.

Abstract

The catalytic role and function of acid sites in solid acid catalysts, such as zeolites, are well understood in the context of heterogeneous catalytic reactions. But although many studies have highlighted the importance of acid sites, their catalytic effects in electrocatalytic reactions have rarely been investigated. In this work, a novel catalyst synthesis strategy is developed, integrating metal sites with acid sites for application in the electrocatalytic glycerol oxidation reaction (EGOR). Specifically, an ordered microporous carbon support containing acidic aluminum sites (AlYTC) is prepared through a nanocasting approach using a sacrificial zeolite template. Platinum (Pt) nanoclusters are then deposited onto the AlYTC support, forming a structure that exposes both acid sites and Pt nanoclusters on a zeolite-templated 3D carbon framework (PtAlYTC). The prepared PtAlYTC catalyst demonstrates a turnover frequency (TOF, s^-1) 30 times higher and a reaction rate ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <semantics><mrow><mi>μ</mi> <mi>m</mi> <mi>o</mi> <mi>l</mi> <mspace></mspace> <msubsup><mi>g</mi> <mrow><mi>p</mi> <mi>t</mi></mrow> <mrow><mo>-</mo> <mn>1</mn></mrow> </msubsup> <msup><mi>s</mi> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> </mrow> <annotation>$\mu mol\;g_{pt}^{ - 1}{s^{ - 1}}$</annotation></semantics> </math> ) 17 times greater than those of a Pt catalyst lacking acid sites (PtYTC) in the EGOR. First-principles density functional theory (DFT) calculations indicate that the combination of Pt sites and acidic Al sites lowers the Gibbs free energy of key reaction steps, improves charge transfer, and strengthens hydrogen adsorption, thereby significantly enhancing the catalytic performance in EGOR.