Carbon monoxide (CO) oxidation is crucial for pollutant removal and hydrogen purification. In recent years, copper–cerium (Cu–Ce)-mixed oxide catalysts have attracted significant attention due to their excellent activity and stability in CO oxidation. This study presents an innovative, environmentally friendly electrosynthesis method for producing stable, structured Cu–Ce catalysts in mesh form. This approach addresses the limitations of traditional pellet catalysts, such as fragility and poor thermal conductivity. The results demonstrated that incorporating cerium (Ce) enhanced the catalytic activity for CO oxidation threefold. A series of in situ characterizations revealed that the introduction of Ce led to the formation of a Cu–Ce mixed oxide solid solution, which significantly improved catalytic performance. Furthermore, higher pretreatment temperatures facilitated the decomposition of Ce compounds (nitrate and hydroxide), which promotes the formation of Cu–Ce solid solutions and increases the concentration of active intermediate species (Cu+‒CO) during the reaction. This process ultimately enhanced the catalyst’s activity.
Carbon capture and storage (CCS) is an advanced environmental technology for mitigating CO2 emissions and addressing climate change. Among the various approaches, adsorption has emerged as a promising method for CO2 capture due to its effectiveness and practicality. This review explores the potential of clay minerals as adsorbents for CO2 capture, providing an in-depth analysis of their inherent properties and the mechanisms involved in adsorption process. The review begins with an introduction to CCS and the concept of adsorption, followed by a detailed examination of various clay minerals, including sepiolite, montmorillonite, bentonite, kaolinite, saponite, halloysite, and illite. Each mineral’s suitability for CO2 adsorption is assessed, highlighting the specific properties that contribute to their performance. The mechanisms of CO2 adsorption including physisorption, chemisorption, ion exchange, pore diffusion, intraparticle diffusion, surface complexation, and competitive adsorption are thoroughly discussed. The review also covers the modification of clay minerals through physical and chemical treatments, amine functionalization, and composite formation to enhance their CO2 adsorption capacity. Additionally, regeneration methods such as temperature-swing adsorption (TSA), pressure-swing adsorption (PSA), and purging are discussed, along with CO2 recovery and storage techniques for improving energy efficiency. The review concludes with an overview of characterization methods for clay-based adsorbents and potential applications, while addressing the challenges and future trends in the field. This work emphasizes the promising role of clay-based adsorbents in advancing CCS technology.
Alkaline electrolytic hydrogen production has emerged as one of the most practical methods for industrial-scale hydrogen production. However, the initial hydrolysis dissociation in alkaline media impedes the hydrogen evolution reaction (HER) kinetics of commercial catalysts. To overcome this limitation, this study focuses on the development of a highly efficient electrocatalyst for alkaline HER. Ni-based intermetallic compounds exhibit remarkable catalytic activity for HER, with the NiMo alloy being among the most active catalysts in alkaline environments. Here, we designed and fabricated self-supported multiscale porous NiZn/NiMo intermetallic compounds on a metal foam substrate using a versatile dealloying method. The resulting electrode exhibits excellent HER activity, achieving an overpotential of just 204 mV at 1000 mA/cm2, and demonstrates robust long-term catalytic stability, maintaining performance at 100 mA/cm2 for 400 h in an alkaline electrolyte. These findings underscore the potential of nanosized intermetallic compounds fabricated via a dealloying approach to deliver exceptional catalytic performance for alkaline water electrolysis.
The NiZn/NiMo double intermetallic composite is fabricated via aversatile dealloying route. Leveraging the high intrinsic activity of theintermetallic and the increased density of active sites provided bymultiscale porous architecture, the resulting NiZn/NiMo electrode exhibitssignificantly lower overpotential and long-term catalytic stability towardalkaline HER. The intermetallic electrode demonstrates unique intrinsiccatalytic activity for HER and exceptional corrosion resistance.
In the field of material sciences, nano-based formulations have attracted the attention of researchers, as they are highly suitable for applications in different fields. Conventionally, physical and chemical techniques have been employed to synthesize silver nanoparticles (AgNPs). However, they use hazardous and poisonous ingredients, which are toxic to human health and the environment. Therefore, it necessitates the development of an eco-friendly and economical method for the fabrication of silver nanoparticles. Biogenic AgNPs have been synthesized using plants and microorganisms due to the presence of reducing agents such as metabolites and enzymes in their extracts. The size, shape, and other properties of the biogenic AgNPs have been characterized using various biophysical techniques. AgNPs are widely used to treat infections and diseases in humans and plants. They have demonstrated antifungal and antibacterial activities and, therefore, have been applied in various therapeutic applications like the treatment of cancer, wound dressing, orthopedic and cardiovascular implants, and dental composites. Biogenic AgNPs have been applied for the remediation of environmental pollution, including that of water and air via the detoxification of synthetic dyes and other contaminants. They have improved seed germination and plant growth after application as nanofertilizers and nano-pesticides, as well as in masking the effects of stress. This review describes various biological routes used in the green synthesis of silver nanoparticles and their potential applications in agricultural, environmental, and medical fields.
The oxygen evolution reaction (OER), a critical half-reaction in water electrolysis, has garnered significant attention. However, sluggish OER kinetics has emerged as a major impediment to efficient electrochemical energy conversion. There is an urgent need to design novel electrocatalysts with optimized OER kinetics and enhanced intrinsic activity to improve overall OER performance. Herein, one-dimensional (1D) nanocomposites with high electrocatalytic activity were developed through the deposition of CoFePBA nanocubes onto the surface of MnO2 nanowires. The electronic structure of the nanocomposite surface was modified, and the synergistic effects between transition metals were leveraged to enhance catalytic activity through the deposition of Prussian blue analog (PBA) nanocubes on manganese dioxide nanowires. Specifically, CoFePBA featured an open crystal structure that offered numerous electrochemical active sites and efficient charge transfer pathways. Additionally, the synergistic interactions between Co and Fe significantly reduced the OER overpotential. Additionally, the 1D rigid MnO2 acted as protective armor, ensuring the stability of active sites within CoFePBA during the OER. The synthesized MnO2@CoFePBA achieved an overpotential of 1.614 V at 10 mA/cm2 and a small Tafel slope of 94 mV/dec and demonstrated stable performance for over 200 h. This work offers new insights into the rational design of various PBA-based nanocomposites with high activity and stability.
The sluggish bidirectional conversion rate between Li2Sn (2 ≤ n ≤ 4) and Li2S, coupled with the uncontrolled deposition of Li2S, significantly impedes the realization of high-performance lithium–sulfur batteries (LSBs). In this study, a metal–organic framework was employed as a precursor for the synthesis of a CoOx–CeO2−y/C (0 < x < 3/2, 0 < y < 1/2) heterojunction via pyrolysis, which was subsequently introduced onto the cathode side of the polypropylene (PP) separator in LSBs. The modification of CoOx–CeO2−y/C enhances the kinetics of converting of Li2Sn to Li2S during the discharge process. The Tafel slope for the Li2S deposition reaction is reduced to 52.1 mV/dec, representing a 56.6% decrease compared to LSBs with bare PP separator. Conversely, during the charging process, the modification lowers the energy barrier for the Li2S decomposition reaction, with the activation energy reduced to 6.12 kJ/mol, indicating a 70.3% decrease relative to LSBs with PP separator only. Consequently, more Li2S is promoted to undergo decomposition. The CoOx–CeO2−y/C heterojunction facilitates uniform deposition of Li2S, featuring fine particles and a uniform distribution, after brief potentiostatic charging for decomposition, thereby effectively mitigating the deactivation of sulfur species. Thanks to the enhanced bidirectional conversion of lithium polysulfides (LiPS) facilitated by the CoOx–CeO2−y/C modification layer, the (−)Li|CoOx–CeO2−y/C@PP|S(+) coin cell maintains a Coulombic efficiency of 90.4% after 500 cycles at a current density of 1 C, exhibiting a low capacity-decay rate of only 0.081% per cycle, thereby demonstrating excellent long-cycle stability.