3D Printed Nickel-Molybdenum-Based Electrocatalysts for Hydrogen Evolution at Low Overpotentials in a Flow-Through Configuration

Additive Manufacturing: A Paradigm Shift in Revolutionizing Catalysis with 3D Printed Photocatalysts and Electrocatalysts Toward Environmental Sustainability

Semiconductor-based materials utilized in photocatalysts and electrocatalysts present a sophisticated solution for efficient solar energy utilization and bias control, a field extensively explored for its potential in sustainable energy and environmental management. Recently, 3D printing has emerged as a transformative technology, offering rapid, cost-efficient, and highly customizable approaches to designing photocatalysts and electrocatalysts with precise structural control and tailored substrates. The adaptability and precision of printing facilitate seamless integration, loading, and blending of diverse photo(electro)catalytic materials during the printing process, significantly reducing material loss compared to traditional methods. Despite the evident advantages of 3D printing, a comprehensive compendium delineating its application in the realm of photocatalysis and electrocatalysis is conspicuously absent. This paper initiates by delving into the fundamental principles and mechanisms underpinning photocatalysts electrocatalysts and 3D printing. Subsequently, an exhaustive overview of the latest 3D printing techniques, underscoring their pivotal role in shaping the landscape of photocatalysts and electrocatalysts for energy and environmental applications. Furthermore, the paper examines various methodologies for seamlessly incorporating catalysts into 3D printed substrates, elucidating the consequential effects of catalyst deposition on catalytic properties. Finally, the paper thoroughly discusses the challenges that necessitate focused attention and resolution for future advancements in this domain.

Bubbles in Porous Electrodes for Alkaline Water Electrolysis

Porous electrodes with high specific surface areas have been commonly employed for alkaline water electrolysis. The gas bubbles generated in electrodes due to water electrolysis, however, can screen the reaction sites and hinder reactant transport, thereby deteriorating the performance of electrodes. Hence, an in-depth understanding of the behavior of bubbles in porous electrodes is of great importance. Nevertheless, since porous electrodes are opaque, direct observation of bubbles therein is still a challenge. In this work, we have successfully captured the behavior of bubbles in the pores at the side surfaces of nickel-based porous electrodes. Two types of porous electrodes are employed: the ones with straight pores along the gravitational direction and the ones with tortuous pores. In the porous electrodes with tortuous pores, the moving bubbles are prone to collide with the solid matrix, thereby leading to the accumulation of bubbles in the pores and hence bubble trapping. By contrast, in the porous electrodes with straight pores, bubbles are seldom trapped; and when two bubbles near the wall surfaces coalesce, the merged bubble can jump away from the wall surfaces, releasing more active surfaces for reaction. As a result, the porous electrodes with straight pores, although with lower specific surface areas, are superior to those with tortuous pores. The relationship among the pore structures of porous electrodes, bubble behavior, and electrode performance disclosed in this work provides deep insights into the design of porous electrodes.

Development of MoS2-stainless steel catalyst by 3D printing for efficient destruction of organics via peroxymonosulfate activation

Herein, a novel MoS2-stainless steel composite material was first synthetized via a 3D printing method (3DP MoS2-SS) for peroxymonosulfate (PMS) activation and organics degradation. Compared with MoS2-SS powder/PMS system (0.37 g/(m2/min)), 4.3-fold higher kFLO/SBET value was obtained in 3DP MoS2-SS/PMS system (1.60 g/(m2/min), resulting from the superior utilization of active sites. We observed that 3DP MoS2-SS significantly outperformed the 3DP SS due to the enhanced electron transfer rate and increased active sites. Moreover, Mo4+ facilitated the Fe2+/Fe3+ cycle, resulting in the rapid degradation of florfenicol (FLO). Quenching experiments and electron paramagnetic resonance spectra indicated that •OH, SO4•-, O2•- and 1O2 were involved in the degradation of FLO. The effect of influencing factors on the degradation of FLO were evaluated, and the optimized degradation efficiency of 98.69% was achieved at 1 mM PMS and pH of 3.0. Six degradation products were detected by UPLC/MS analyses and several possible degradation pathways were proposed to be the cleavage of C-N bonds, dechlorination, hydrolysis, defluorination and hydroxylation. In addition, 3DP MoS2-SS/PMS system also demonstrated superior degradation performance for 2-chlorophenol, acetaminophen, ibuprofen and carbamazepine. This study provided deep insights into the MoS2-SS catalyst prepared by 3DP technology for PMS activation and FLO-polluted water treatment.

Carbon Aerogels as Electrocatalysts for Sustainable Energy Applications: Recent Developments and Prospects

Carbon aerogel (CA) based materials have multiple advantages, including high porosity, tunable molecular structures, and environmental compatibility. Increasing interest, which has focused on CAs as electrocatalysts for sustainable applications including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and CO₂ reduction reaction (CO₂RR) has recently been raised. However, a systematic review covering the most recent progress to boost CA-based electrocatalysts for ORR/OER/HER/CO₂RR is now absent. To eliminate the gap, this critical review provides a timely and comprehensive summarization of the applications, synthesis methods, and principles. Furthermore, prospects for emerging synthesis, screening, and construction methods are outlined.