High temperature thermo-photocatalysis driven carbon removal in direct biogas fueled solid oxide fuel cells

Approaches for Enhancing Wastewater Treatment of Photocatalytic Fuel Cells: A Review

Environmental pollution and energy crises have garnered global attention. The substantial discharge of organic waste into water bodies has led to profound environmental contamination. Photocatalytic fuel cells (PFCs) enabling the simultaneous removal of refractory contaminants and recovery of the chemical energy contained in organic pollutants provides a potential strategy to solve environmental issues and the energy crisis. This review will discuss the fundamentals, working principle, and configuration development of PFCs and photocatalytic microbial fuel cells (PMFCs). We particularly focus on the strategies for improving the wastewater treatment performance of PFCs/PMFCs in terms of coupled advanced oxidation processes, the rational design of high-efficiency electrodes, and the strengthening of the mass transfer process. The significant potential of PFCs/PMFCs in various fields is further discussed in detail. This review is intended to provide some guidance for the better implementation and widespread adoption of PFC wastewater treatment technologies.

Carbon Deposition Mitigation Strategies in Proton-Conducting Solid Oxide Fuel Cells: A Case Study with Biomass Fuels

Methanol and ethanol, when used as biomass fuels, demonstrate distinct benefits compared to hydrogen in proton-conducting solid oxide fuel cells (PCFCs) applications. Nevertheless, employing these biomass fuels in PCFCs encounters a significant obstacle due to carbon deposition, adversely affecting the cells' longevity. To mitigate this issue, a dendritic pore channel anode design was implemented to optimize the fuel distribution and utilization efficiency. Additionally, the approach incorporates a co-reforming strategy of fuel and steam, operating the cell under stable output current conditions to mitigate carbon deposition in the cell. Furthermore, the integration of Ru-GDC nanofiber catalysts enhanced the cell's resistance to carbon deposition and improved its stability. Techniques such as argon and oxygen purging, along with thermal regeneration, were investigated for carbon removal. These approaches have proven to be effective in diminishing carbon buildup and restoring cell functionality. Applying these strategies, PCFCs equipped with Ru-GDC fiber catalysts, operating at a stable 700 °C current, demonstrated prolonged stability for 117 h with methanol and 96 h with ethanol, markedly surpassing the performance of untreated cells. These advancements not only alleviate carbon deposition issues in PCFCs utilizing methanol and ethanol but also enhance the potential of biomass fuels in PCFC applications.

Coupling photocatalytic and electrocatalytic oxidation towards simultaneous removal of humic acid and ammonia-nitrogen in landscape water

Aiming to bring photocatalytic and electrocatalytic oxidation processes into solving practical issue of organics and ammonia-nitrogen pollution in landscape water that resulting in algae bloom and eutrophication, this work firstly investigates photocatalytic oxidation of humic acid and electrochemical oxidation of ammonia upon optimization of each process parameters, respectively. The platinum modified titania (Pt/TiO₂) exhibits improved activity than pure titania and CuO_x, MnO_x and NiO_x modified titania for decomposition of humic acid. As an application-oriented study, this work has developed a simple and effective brushing and annealing method for immobilization of TiO₂ and Pt/TiO₂ onto ceramic foam for further application. In addition, the RuO₂-IrO₂/Ti electrode presents the best electrocatalytic activity compared with RuO₂/Ti and IrO₂/Ti electrodes in terms of ammonia oxidation, and the ammonia conversion pathways have been studied. Lastly, an integrated and enlarged reactor system employing optimized photocatalytic ceramic foam and stable electrodes has been developed for simultaneous oxidation of humic acid and ammonia-nitrogen in water circulated flow condition, based on cooperative production of reactive oxidant species between photocatalysis and electrocatalysis. The results show that coupled photocatalytic and electrocatalytic oxidation is a promising approach for treatment of organic matter and inorganic ammonia nitrogen in landscape water.