Analysis of oxygen evolving catalyst coated membranes with different current collectors using a new modified rotating disk electrode technique

One-step synthesis of Pt-Nd co-doped Ti/SnO2-Sb nanosphere electrodes used to degrade nitrobenzene

Ti/SnO2-Sb electrodes possess high catalytic activity and efficiently degrade nitrobenzene (NB); however, their low service life limits their wide application. In this study, we used one-step hydrothermal synthesis to successfully prepare Pt-Nd co-doped Ti/SnO2-Sb nanosphere electrodes. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were applied to characterize the surface morphology, microstructure, and chemical composition of the electrodes, respectively. The electrochemical activity and stability of the electrodes were characterized via linear sweep and cyclic voltammetry, electrochemical impedance spectroscopy, and an accelerated service life test; their performance for NB degradation was also studied. An appropriate amount of Pt-Nd co-doping refined the average grain size of SnO2 and formed a uniform and compact coating on the electrode surface. The oxygen evolution potential, total voltammetric charge, and electron transfer resistance of the Ti/SnO2-Sb-Nd-Pt electrodes were 1.88 V, 3.77 mC/cm2, and 11.50 Ω, respectively. Hydroxy radical was the main active radical species during the electrolytic degradation of nitrobenzene with Ti/SnO2-Sb-Nd-Pt. After Pt-Nd co-doping, the accelerated service life of the electrodes was extended from 8.0 min to 78.2 h (500 mA/cm2); although the NB degradation rate decreased from 94.1 to 80.6%, the total amount of theoretical catalytic degradation of NB in the effective working time increased from 17.4 to 8754.1 mg/cm2. These findings reveal good application potential for the electrodes and provide a reference for developing efficient and stable electrode materials.

Water electrolysis: from textbook knowledge to the latest scientific strategies and industrial developments

Replacing fossil fuels with energy sources and carriers that are sustainable, environmentally benign, and affordable is amongst the most pressing challenges for future socio-economic development. To that goal, hydrogen is presumed to be the most promising energy carrier. Electrocatalytic water splitting, if driven by green electricity, would provide hydrogen with minimal CO2 footprint. The viability of water electrolysis still hinges on the availability of durable earth-abundant electrocatalyst materials and the overall process efficiency. This review spans from the fundamentals of electrocatalytically initiated water splitting to the very latest scientific findings from university and institutional research, also covering specifications and special features of the current industrial processes and those processes currently being tested in large-scale applications. Recently developed strategies are described for the optimisation and discovery of active and durable materials for electrodes that ever-increasingly harness first-principles calculations and machine learning. In addition, a technoeconomic analysis of water electrolysis is included that allows an assessment of the extent to which a large-scale implementation of water splitting can help to combat climate change. This review article is intended to cross-pollinate and strengthen efforts from fundamental understanding to technical implementation and to improve the 'junctions' between the field's physical chemists, materials scientists and engineers, as well as stimulate much-needed exchange among these groups on challenges encountered in the different domains.

Rapid mass production of iron nickel oxalate nanorods for efficient oxygen evolution reaction catalysis

Using a coprecipitation method we synthesized an oxalate, which has a good catalytic performance for oxygen evolution in an alkaline electrolyte. This method can efficiently synthesize a large number of electrocatalysts in a short time.

Water electrolysers with closed and open electrochemical systems

Green hydrogen production using renewables-powered, low-temperature water electrolysers is crucial for rapidly decarbonizing the industrial sector and with it many chemical transformation processes. However, despite decades of research, advances at laboratory scale in terms of catalyst design and insights into underlying processes have not resulted in urgently needed improvements in water electrolyser performance or higher deployment rates. In light of recent developments in water electrolyser devices with modified architectures and designs integrating concepts from Li-ion or redox flow batteries, we discuss practical challenges hampering the scaling-up and large-scale deployment of water electrolysers. We highlight the role of device architectures and designs, and how engineering concepts deserve to be integrated into fundamental research to accelerate synergies between materials science and engineering, and also to achieve industry-scale deployment. New devices require benchmarking and assessment in terms of not only their performance metrics, but also their scalability and deployment potential.

Clean production of porous-Al(OH)3 from fly ash

Fly ash is one of the largest solid waste and causes serious environment problems. Extraction of Al(OH)₃ from fly ash is beneficial to environment and economy. We developed a clean electrolysis method to generate hydroxyl groups in situ to extract Al(OH)₃ from fly ash leachate without adding chemicals or using expensive membranes, avoiding the introduction of new impurities, secondary pollutants generation, and membrane limitations. Batch experiments yielded porous electrolytic products with BET surface areas from 11.7610 to 25.5267 m²/g, pore volumes from 0.1935 to 0.1643 cm³/g and pore sizes from 65.7960 to 25.7434 nm. The composition of the electrolytic products was 86.43 wt% Al(OH)₃, 9.00 wt% SO₃, 1.67 wt% Fe(OH)₃, and 0.29 wt% Ca(OH)₂. The current efficiency was 90.51 % under optimized conditions of c (Al³⁺) = 0.1 M, t =2 h, and J = 750 A/m². Mean particle size was from 24.1-98.1 μm. Impurities mainly affected the composition of the electrolytic products. The OH- generated by H₂O reduction reacted with Al³⁺, Fe³⁺, and Ca²⁺ to generate a hydroxide. Fe³⁺ preceded Ca²⁺ into the hydroxide. H₂ released continuously from H₂O reduction, resulting in a porous hydroxide. The wastewater was reused as a leaching reagent to promote zero-pollution discharge.