Recently, the interest in ethanol production from renewable natural sources in Thailand has been receiving much attention as an alternative form of energy. The low-cost accessibility of ethanol has been seen as an interesting topic, leading to the extensive study of the formation of distinct chemicals, such as ethylene, diethyl ether, acetaldehyde, and ethyl acetate, starting from ethanol as a raw material. In this paper, ethanol dehydrogenation to acetaldehyde in a one-step reaction was investigated by using commercial activated carbon with four different metal-doped catalysts. The reaction was conducted in a packed-bed micro-tubular reactor under a temperature range of 250–400 °C. The best results were found by using the copper doped on an activated carbon catalyst. Under this specified condition, ethanol conversion of 65.3% with acetaldehyde selectivity of 96.3% at 350 °C was achieved. This was probably due to the optimal acidity of copper doped on the activated carbon catalyst, as proven by the temperature-programmed desorption of ammonia (NH₃-TPD). In addition, the other three catalyst samples (activated carbon, ceria, and cobalt doped on activated carbon) also favored high selectivity to acetaldehyde (>90%). In contrast, the nickel-doped catalyst was found to be suitable for ethylene production at an operating temperature of 350 °C.

The strategy of defect engineering is increasingly recognized for its pivotal role in modulating the electronic structure, thereby significantly improving the electrocatalytic performance of materials. In this study, we present defect-enriched nickel and iron oxides as highly active and cost-effective electrocatalysts, denoted as Ni_0.6Fe_2.4O₄@NC, derived from NiFe-based metal-organic frameworks (MOFs) for oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). XANES and EXAFS confirm that the crystals have a distorted structure and metal vacancies. The cation defect-rich Ni_0.6Fe_2.4O₄@NC electrocatalyst exhibits exceptional ORR and OER activities (ΔE = 0.68 V). Mechanistic pathways of electrochemical reactions are studied by DFT calculations. Furthermore, a rechargeable zinc-air battery (RZAB) using the Ni_0.6Fe_2.4O₄@NC catalyst demonstrates a peak power density of 187 mW cm^-2 and remarkable long-term cycling stability. The flexible solid-state ZAB using the Ni_0.6Fe_2.4O₄@NC catalyst exhibits a power density of 66 mW cm^-2. The proposed structural design strategy allows for the rational design of electronic delocalization of cation defect-rich NiFe spinel ferrite attached to ultrathin N-doped graphitic carbon sheets in order to enhance active site availability and facilitate mass and electron transport.