Fuel Cell Reactors for the Clean Cogeneration of Electrical Energy and Value-Added Chemicals

Abstract

Fuel cell reactors can be tailored to simultaneously cogenerate value-added chemicals and electrical energy while releasing negligible CO2 emissions or other pollution; moreover, some of these reactors can even “breathe in” poisonous gas as feedstock. Such clean cogeneration favorably offsets the fast depletion of fossil fuel resources and eases growing environmental concerns. These unique reactors inherit advantages from fuel cells: a high energy conversion efficiency and high selectivity. Compared with similar energy conversion devices with sandwich structures, fuel cell reactors have successfully “hit three birds with one stone” by generating power, producing chemicals, and maintaining eco-friendliness. In this review, we provide a systematic summary on the state of the art regarding fuel cell reactors and key components, as well as the typical cogeneration reactions accomplished in these reactors. Most strategies fall short in reaching a win–win situation that meets production demand while concurrently addressing environmental issues. The use of fuel cells (FCs) as reactors to simultaneously produce value-added chemicals and electrical power without environmental pollution has emerged as a promising direction. The FC reactor has been well recognized due to its “one stone hitting three birds” merit, namely, efficient chemical production, electrical power generation, and environmental friendliness. Fuel cell reactors for cogeneration provide multidisciplinary perspectives on clean chemical production, effective energy utilization, and even pollutant treatment, with far-reaching implications for the wider scientific community and society. The scope of this review focuses on unique reactors that can convert low-value reactants and/or industrial wastes to value-added chemicals while simultaneously cogenerating electrical power in an environmentally friendly manner. Graphical Abstract A schematic diagram for the concept of fuel cell reactors for cogeneration of electrical energy and value-added chemicals

Four Lanthanide(III) Metal–Organic Frameworks Fabricated by Bithiophene Dicarboxylate for High Inherent Proton Conduction

“…With their environmental and energy efficiency benefits, fuel cells are vital for modern society’s sustainable development. A critical component of these devices is materials with high proton conductivity (σ), which currently pose a bottleneck in the technological evolution of fuel cells. − …”

Prominent Intrinsic Proton Conduction in Two Robust Zr/Hf Metal–Organic Frameworks Assembled by Bithiophene Dicarboxylate

“…Researchers have been searching for alternative energy sources in recent years due to the rise in global energy demand brought on by fast industrialization and the poor environmental conditions that followed. Fuel cells are considered possible candidates since they are a technology that directly transforms chemical energy into electrical energy. − Proton exchange membrane fuel cells are distinguished by their high power density and energy conversion efficiency, low emissions and heat dissipation, and little noise pollution. − Although Nafion and Nafion-like organic polymers show great potential as fuel cell conductive materials, − there are certain drawbacks in practical and large-scale applications: (i) complex synthesis process and high cost of raw materials; (ii) high water solubility and low operating temperature; (iii) certain amorphous materials making it challenging to comprehend their proton conduction process; (iv) slight fluctuations in temperature may lead to clogging of the electrodes and a reduction in the performance of the battery; and (v) catalysts, which are widely used, may cause poisoning. As a result, scientists are looking for new porous materials that are simple, highly stable, and conductive.…”

“…Metal−organic frameworks (MOFs) have drawn more research attention among the lately suggested crystalline materials 16−20 because of their tunable functionality, intrinsic proton transport channels, and visible structures. 21−25 With the accumulation of extensive expertise in the study of proton-conducting MOFs in recent times, it has been demonstrated that altering the proton concentration or mobility can result in increased proton conductivity (σ), 26−34 and the following strategies are usually employed: (1) introducing proton carriers (H 3 O + , NH 4 + , nonvolatile acids, etc.) into the MOFs pores to obtain a higher carrier concentration, forming a H-bonding network with the framework or guest water molecules, which in turn achieves efficient σ; (2) grafting acidic functional groups (−SO 3 H, −PO 3 H 2 , −COOH, etc.)…”

The emerging Sr2FeMoO6-based electrocatalysts for solid oxide electrochemical cell: synthesis, modulation and applications

“…The presence of the electrolyte can avoid the direct contact between the fuel gas and the oxidizing gas and prevent the direct contact between the fuel electrode and the air electrode from an internal short circuit phenomenon. The electrode part (fuel electrode and air electrode) is the site of gas adsorption, diffusion, activation, transformation and dissociation, which is the place where electrochemical reactions occur [5,6] . SOFC can efficiently and cleanly use hydrogen energy and hydrocarbon fuels at high temperatures, convert chemical energy into electrical energy, and complete high-efficiency power generation.…”