Atomically dispersed transition metal-nitrogen-carbon catalysts are emerging as low-cost electrocatalysts for the oxygen reduction reaction in fuel cells. However, a cost-effective and scalable synthesis strategy for these catalysts is still required, as well as a greater understanding of their mechanisms. Herein, iron, nitrogen co-doped carbon spheres (Fe@NCS) have been prepared via hydrothermal carbonization and high-temperature post carbonization. It is determined that FeN 4 is the main form of iron existing in the obtained Fe@ NCS. Two different precursors containing Fe 2+ and Fe 3+ are compared. Both chemical and structural differences have been observed in catalysts starting from Fe 2+ and Fe 3+ precursors. Fe 2+ @NCS-A (starting with Fe 2+ precursor) shows better catalytic activity for the oxygen reduction reaction. This catalyst is studied in an anion exchange membrane fuel cell. The high open-circuit voltage demonstrates the potential approach for developing high-performance, low-cost fuel cell catalysts.

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X-ray Raman scattering (XRS) spectroscopy is an emerging inelastic scattering technique which uses hard X-rays to study the X-ray absorption edges of low-Z elements (e.g. C, N, O) in bulk....

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Biomass from harvested road-verge herbage has potential value as a feedstock for anaerobic digestion (AD) energy plants. However, the proximity to road traffic related pollution sources introduces the possibility of contamination by potentially toxic elements and polycyclic aromatic hydrocarbons. Potential sources of pollution from road traffic emissions are identified and the consequent likelihood of certain contaminants being present at elevated levels is assessed. Samples of road verge biomass harvested from selected locations in Lincolnshire UK for use in AD plants were analysed to produce a set of measurements for the presence of the contaminants of interest. The measured levels of these contaminants are compared to reported background levels in UK herbage and soils to assess if there is significant increased concentration in road-verge biomass. Samples of digestate from an AD plant using the road-verge biomass as feedstock were also analysed to determine if there is notable risk of transfer and concentration of contaminants into agricultural land where the digestate may be used for fertilisation. While elevated levels of contaminants were detected, they were not found in concentrations on road verge biomass at high enough levels to cause adverse effects or concerns for its safe use as an AD feedstock.