A review to elucidate the influence of promoters on the acidity/basicity, reducibility, and metal-support interaction of catalysts in methane dry reforming

Past researches had identified the importance the acidity/basicity, reducibility, and metal-support interactions of catalyst in impacting its performances in methane dry reforming (MDR). This review provides an in-depth overview of the roles of acidity/basicity in MDR reactions, focusing on their impacts on reducibility and metal-support interactions. The discussion is categorized based on the incorporated promoter, including rare earth metals, transition metals, noble metals, and alkali earth metals. The acidity and basicity of catalysts play a crucial role in MDR reactions. Brønsted acidic sites enhance catalyst activation, reducibility, and metal-support interaction, while Lewis acidic sites facilitate CH₄ and CO₂ activation more prominently. However, excessive acidity can lead to reduced reducibility and increased catalyst deactivation. Also, basic sites formed via basic metal oxides can enhance reducibility, metal-support interaction, and overall catalytic performance. A moderate level of basicity is favoured, as it can effectively modulate reducibility and metal-support interaction without inducing excessive metal dispersion or deactivation. Understanding the complex interplay between acidity and basicity is essential for designing high-performance MDR catalysts with improved reducibility, metal-support interaction, stability, and activity. Future research directions include novel promoter developments, incorporation of machine learning, and investigation of catalyst deactivation mechanisms to ensure the sustainability of MDR technology.