However, carbon-based electrocatalysts that are capable of generating H2O2 at industrial-level current densities (>300 mA cm−2) with high selectivity and long-term stability remain to be discovered.

The gap

Consensus across the literature

Supporting evidence — 3 representative gaps

• PGM-Free Biomass-Derived Electrocatalysts for Oxygen Reduction in Energy Conversion Devices: Promising Materials (2024) · doi

  High catalytic activity is the most important requirement for ORR electrocatalysts, which require specific physical and chemical descriptors such as high specific surface area and hierarchical porosity, high pyridinic-N content, high site density and turn-over frequency. Further, binding ener- gies of O2 to active sites needs to be moderate according to the Sabatier Principle [72] to obtain the highest activity. Electrochemical Energy Reviews (2024) 7:1 Page 41 of 52 1 However, durability and selectivity are also important. For example, selectivity for 4-electron reduction of ORR is desired in a fuel cell. An overview of a number of electrocatalysts obtained by biomass has been reviewed. We have highlighted several types of biomass and different synthetic methods and the role played by these in the structure and their electrocatalytic activity. The enhancement of ORR performance in fuel cells and metal air batteries must be the main driving force for the technological progression in this sector, requiring more efficient, scalable, sustainable and economical materials. The direct preparation of carbonaceous materials from bio- mass would have a potential advantage on these applications. Because of the renewable nature of the biomass, precursors are easy to produce. Under a controlled pyrolysis process, the structural properties of the biomass can be retained in the final porous carbon material (memory effect), which plays an utmost role in PEMFC/AEMFC and ZAB. The observed trends show that performance improves after doping and/ or co-doping with heteroatoms, but yet not enough. These materials suffer from degradation due to corrosion of carbon and leaching of transition metals, even if in a lesser extent compared to Pt/C-based electrocatalysts. This is especially important in acid electrolytes. Already existing commercial PGM-free electrocatalysts outperformed the results obtained so far with biomass-derived materials. However, it is cru- cial to note that a critical evaluation is important, to avoid the mistake of considering every biomass, even laughable ones (such as hairs, urine, guano), as a valid candidate for electrocatalysts’ synthesis, as pointed out by Pumera and coworkers [288]. Biomass heterogeneity and variability of chemical characteristics are still an issue. The economic feasibility of biomass recycling for elec- trocatalysts production is still challenging to asses due to the limited data and few full-scale projects in operation. Moreo- ver, the existing performance gap between biomass-derived electrocatalysts and commercial ones is still too high yet to push a process scale-up. In addition, the technology readiness level (TRL) of the examined processes in this review is still too low, below level 3 to 4 (“experimental proof of concept” and “technology validated in lab”) to support a solid economic feasibility analysis [289]. Still very far from TRL values 8 and 9 (“system

  Keywords: biomass electrocatalysts high still important materials activity performance specific chemical selectivity fuel obtained role process
• Electrochemically synthesized H2O2 at industrial-level current densities enabled by in situ fabricated few-layer boron nanosheets (2024) · doi

  However, carbon-based electrocatalysts that are capable of generating H2O2 at industrial-level current densities (>300 mA cm−2) with high selectivity and long-term stability remain to be discovered.

  Keywords: carbon based electrocatalysts capable generating industrial level current densities high selectivity long term stability remain
• Electrocatalytic Upgrading of Plastic and Biomass‐Derived Polyols to Formamide under Ambient Conditions (2024) · doi

  Abstract Electrocatalytic upgrading of wasted plastic and renewable biomass represents a sustainable method to produce chemicals but is limited to carbohydrates, leaving other value‐added chemicals, such as organonitrogen compounds, being scarcely explored.

  Keywords: chemicals abstract electrocatalytic upgrading wasted plastic renewable biomass represents sustainable produce limited carbohydrates leaving value