On the 3D printed catalyst for biomass-bio-oil conversion: Key technologies and challenges

Abstract

The devastative effects of traditional fossil fuel consumption have made biomass (e.g., plants, wood, and waste) a widely used renewable source of energy. The variety in biomass properties makes tunable catalysts an essential ingredient to promote reactions for desired molecule outputs. Catalysts with optimal catalytic performance are typically structured with complicated morphology, such as high porosity and sophistic pore network, which makes it challenging for catalyst fabrication. Recent progress in utilizing 3D printing as the fabrication method has demonstrated great potential of handling the complex structure while improving catalytic performance; however, rare work has focused on biomass-bio-oil conversion (BBC). With the aim of developing the optimal structured catalysts for BBC applications, this paper particularly reviewed 1) typical catalysts used for biomass conversion applications, 2) 3D printed catalysts, and 3) design and optimization of structured catalysts. It is found that the BBC is often isolated from manufacturing and focused more on different catalyst composition with transition metals to provide the desired catalyst architecture and further to improve upgrading of the BBC product. Current work on 3D-printed catalysts also show deficiency in several aspects including formation of coke and catalyst deactivation, lack of a comprehensive design for the catalyst structure (e.g., mostly 2D structures), absence of manufacturing constraints in design operation, and insufficient resolution of 3D printing methods. To solve these issues, several potential research directions and opportunities are discussed at the end of the study.