Metal‐free carbonaceous catalytic materials: biomass feedstocks for a greener future

Metal-free catalytic systems (MFCS) have emerged as sustainable and cost-efficient heterogeneous catalysts, particularly in the case of carbonaceous materials with oxygen, nitrogen, boron, sulfur or phosphorus functionalities. This contribution aims to provide a general overview of the recent advances on the design of such materials, with emphasis on those derived from biomass waste and on the relationship between their structure and their activity. The opportunities of using MFCS in different areas of catalysis, including thermo-, electro-, and photo-catalysis, will be addressed for applications towards the upgrading of renewable feedstocks. This analysis will describe sustainable approaches not only with respect to the nature of catalyst but also for the employment of non-toxic and sustainable precursors, and for the efficiency of the synthetic protocol and its carbon footprint.