Electrocatalysis technology is crucial for energy conversion. However, its widespread application is hindered by the high cost and scarcity of noble metal catalysts. Biogenic siliceous materials, such as diatomite (DT), characterized by hierarchical pore structures and inherent stability, offers a robust platform for developing efficient, cost-effective non-noble metal catalysts. This review systematically summarizes recent advances in the DT functionalization and utilization as a template or precursor for synthesizing porous carbon (PC)-based, silicon-based, and metal compound catalysts. The review specifically evaluates the performance of biogenic siliceous materials in key electrocatalytic reactions, including the oxygen evolution reaction, hydrogen evolution reaction, oxygen reduction reaction, and carbon dioxide reduction reaction. Finally, the review outlines research directions to address current challenges, highlighting the criticality of optimizing structural regulations and controllable synthesis to facilitate the practical application of these electrocatalytic materials.
Exploring highly efficient photocatalytic materials is of utmost importance for the efficient generation of hydrogen peroxide (H2O2) in seawater. However, the catalytic performance of such materials is constrained by low solar energy conversion efficiency and inadequate charge carrier separation. In this study, narrow-bandgap CdS nanoparticles with high reducibility, synthesized via a hydrothermal method, are coupled with Bi2O2CO3 (BOC) nanosheets to construct S-scheme BOC/CdS heterojunctions. These heterojunctions effectively optimize charge transfer, broaden light absorption, accelerate charge separation and migration, maintain strong redox capabilities, and enable dual pathways for two-electron water oxidation and oxygen reduction. Systematic characterizations, including in situ X-ray photoelectron spectroscopy/Fourier transform infrared spectroscopy, Kelvin probe force microscopy, electron spin resonance, and femtosecond transient absorption spectroscopy, are performed to elucidate the H2O2 generation pathways, clarify the charge transfer and separation mechanisms, and confirm the S-scheme mechanism. The optimized BOC/CdS heterojunction demonstrates superior H2O2 production in seawater, reaching 1904 μmol/(g h), which is 17.96-fold that of BOC and 2.13-fold that of pure CdS. Moreover, its performance in seawater is remarkable compared to that in deionized water. Overall, this research presents a viable strategy for designing S-scheme catalysts to enhance H2O2 photosynthesis from seawater.
Conductive hydrogels are vital components in modern electronics and show great promise for wearable sensors. However, their practical use is often limited by the difficulty of balancing mechanical properties and ionic/electronic conductivity. Herein, a dimethyl sulfoxide (DMSO)–regulated polyvinyl alcohol/guar gum (PVA/GG) dual-network conductive hydrogel (D-PVA/GG) was developed. The pre-shielding of intramolecular hydrogen bonds by DMSO induces extended polymer chain conformations, promoting the formation of a robust network and increasing the availability of hydrated hydroxyl groups. This mechanism significantly enhances both the mechanical performance and ionic conductivity of D-PVA/GG. Consequently, D-PVA/GG achieves a tensile strength of 3.82 MPa and a fracture strain of 815%. This strain is five times that of pure PVA hydrogels. D-PVA/GG also attained a conductivity of 1.66 S/m. These results demonstrate the synergistic optimization of the mechanical strength and conductivity. As a wearable sensor, D-PVA/GG can effectively monitor human motions in real time.
Photocatalytic conversion of carbon dioxide (CO2) to methanol is hindered by inefficient charge separation and complex multielectron pathways. To address these challenges, we report a synergistic catalyst design in which cobalt vacancies (VCo) are coupled with indium single atoms (In SAs). VCo sites were precisely constructed on Co3O4 nanosheets using a chlorine cold plasma technique, acting as “atomic sockets” that confine In SAs and form a robust In–O–VCo coordination structure. The resulting In/Co3−xO4 catalyst delivered a high methanol production rate of 466.7 μmol/(g·h) with 92.3% selectivity under simulated solar irradiation, which was eight times greater than that of the vacancy-free catalyst. Mechanistic studies revealed a synergistic functional division: the VCo sites efficiently adsorbed and dissociated H2O to supply protons, whereas the In SAs polarized CO2 and stabilized the critical *COOH intermediate. This synergy of strong electronic metal–support interactions improved charge separation and steered the reaction pathway toward methanol, offering a novel atomic-level strategy for designing highly selective CO2 photoreduction catalysts.
Copper (Cu) has been widely recognized as a promising catalyst for electrocatalytic CO2 reduction (CO2R) into value-added multi-carbon (C2+) chemicals. However, the limited selectivity of C2+ products persists due to the inactivation of precisely designed active sites triggered by uncontrollable reconstruction. Herein, we report the successful synthesis of the electrocatalysts of Lewis-acidic aluminum (Al)-doped copper oxides (AlCuOx) with exposed abundant atomic-scale Al − O − Cu sites. The strong Al − O − Cu bridge bonds effectively suppress surface electrochemical reconstruction, and highly stable Cuδ+ species are obtained. The AlCuOx catalyst exhibits an excellent electrocatalytic CO2R performance, delivering a Faradaic efficiency (FE) for C2+ products of 73.6% (ethylene 54.16% and ethanol 19.44%), at a current density of − 221.7 mA/cm2. The analyses of in situ spectroscopy and theoretical calculations confirm that the high electron localization of Cu active sites in AlCuOx strengthens the interactions between Cu and linearly bonded *CO (*COL) through p − d orbital hybridization, thus facilitating C − C coupling and steering the CO2 electroreduction pathway toward C2+ products. This work provides new insights into constructing reconstruction-resistant Cu-based catalysts that enable efficient and stable CO2-to-C2+ conversion.
The development of sustainable, cost-effective catalytic systems for the electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is pivotal for advancing biomass-based economies and valorizing bio-based platform chemicals. Against the backdrop of intensifying focus on biomass resource recycling, the conversion of lignocellulosic agricultural residues, represented by waste fruit shells, into high-performance catalysts has emerged as a promising strategy, yet existing technologies are hampered by cumbersome processes, excessive energy consumption, and suboptimal catalytic efficiency, limiting scalable industrial application. Herein, we reported the fabrication of high-performance metal-free electrocatalysts using abundant waste fruit shells as the sole precursor, which were specifically designed for the electrochemical selective oxidation of HMF to FDCA. The as-prepared waste fruit shell-derived porous carbon catalyst exhibited exceptional catalytic performance: it achieved a FDCA yield of 96.48% and a Faraday efficiency (FE) of 93.01%, along with robust stability over multiple consecutive reaction cycles, demonstrating its potential for long-term practical application. This work couples agricultural waste upcycling with efficient FDCA synthesis, offering a low-cost green solution and advancing biomass-based circular economy.
Photoelectrocatalytic (PEC) reduction of carbon dioxide (CO2) with water (H2O) into syngas not only alleviates energy and environmental crises but also provides feed gas for producing high-value chemicals. In this study, self-supported Ny-Cu2O/CuFs are successfully prepared using copper foam as a precursor, following a self-assembly strategy to fabricate a PEC system for converting CO2 and H2O into syngas. N-doping facilitates the preferential growth of Cu2O (111) crystal planes in Ny-Cu2O/CuF, resulting in high surface oxygen vacancies. Simultaneously, appropriate surface electronic structure and good light capture capability endow the synthesized material with excellent PEC properties, achieving a syngas yield 2.5 times higher than that of the unmodified CuxO/CuF, with a CO yield of 58.72 μmol/(cm2·h) and the lowest H2/CO ratio of 1.6. This study provides a promising strategy for developing high-performance photocathodes for CO2-efficient conversion.
Sluggish kinetics of water electrolysis is a major challenge in the practical dissociation of water to form gaseous H2 and O2. Electrocatalysts are required for enhancing the performance of the water splitting process. This study addresses this issue by examining the synthesis of ZnS quantum dots (QDs), a metal–organic framework containing Dy (Dy-MOF), and the composite of these species (ZnS@Dy-MOF), as well as their potential use as electrocatalysts for water splitting. ZnS QDs were integrated into the MOF during synthesis to achieve enhanced conductivity and stability, aiming to harness the synergetic effect in the resulting material. The properties of ZnS@Dy-MOF were exploited in practical use to address the urgent demand for effective water splitting catalysts. The morphological, structural, and compositional properties of the ZnS QDs, Dy-MOF, and ZnS@Dy-MOF were examined via various characterization techniques. The ZnS@Dy-MOF composite emerged as the optimal electrocatalyst for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with a low overpotential of 228 mV for the HER and 138 mV for the OER at a current density of 10 mA/cm2. The ZnS@Dy-MOF composite also had a relatively small onset potential of 1.47 V versus RHE with 50 h of electrochemical sustainability. The synergistic interaction between the ZnS QDs and Dy-MOF conferred remarkable catalytic efficiency and significant stability to the electrocatalyst. The foremost objective of this research is to study the extraordinary potential of Dy-MOF and its composites for applications involving water splitting.