Exploiting its exceptional structural tunability and digital manufacturing capability, 3D printing emerges as a transformative technique for the rational design and scalable fabrication of catalytic electrodes tailored for advanced electrochemical energy systems. In this study, hierarchically porous, self-supporting carbon electrodes were fabricated via 3D printing technique in combination with the sequential conformal carbonization. An optimized polymerizable ionic liquid-based ink was employed to produce a 3D printed polymer gel, which was subsequently functionalized with B-containing species. The as-prepared gel was then pyrolyzed to yield B/N-co-doped carbon electrodes with a high surface area possessing micropores, mesopores and macropores. The metal-free cathode demonstrated good performance in electrocatalytic CO₂ reduction, producing syngas with tunable H₂/CO ratios ranging from 0.37 to 2.6, thereby catering to diverse application requirements. This study naturally integrates 3D printing with ionic-liquid chemistry to fabricate customizable metal-free carbon electrodes for efficient CO₂-to-syngas conversion, offering a Power-to-X route to store intermittent renewable electricity as chemical energy and to deliver tunable H₂/CO syngas suitable for downstream fuel and chemical synthesis.

Per- and polyfluoroalkyl substances (PFAS) are generally employed as proton exchange membranes in fuel cell gas sensors, but they suffer from environmental persistence, safety concerns, and high cost. Here, sulfonated poly(ether ether ketone) (SPEEK) is employed to replace the PFAS and a chemically compatible hydroxylated SPEEK ionomer binder is designed to reduce the interfacial resistance at the catalyst–membrane boundary. Due to the high proton conductivity, improved interfacial proton transport and enhanced intrinsic hydrophilicity of SPEEK, the resulting PFAS-free gas sensor exhibits a twofold higher response at 100 ppm H₂S compared to a commercial Nafion benchmark, along with high sensitivity (0.635 µA·ppm^–1) and faster response time (31 s). The device operates stably across 15–95% RH and retains over 90% of its initial response after 60 days. This work establishes SPEEK as a cost-effective, eco-friendly alternative to fluorinated membranes and provides a general interface-engineering strategy for high-performance electrochemical gas sensing.

The hydrogenation of glyoxylate oxime is the energy-intensive step in glycine electrosynthesis. To date, there has been a lack of rational guidance for catalyst design specific to this step, and the unique characteristics of the oxime molecule have often been overlooked. In this study, we initiate a theoretical framework to elucidate the fundamental mechanisms of glycine electrosynthesis across typical transition metals. By comprehensively analyzing the competitive reactions, proton-coupled electron transfer processes, and desorption steps, we identify the unique role of the glyoxylate oxime as a “readily activated molecule”. This inherent property positions Ag, featuring weak adsorption characteristics, as the “dream” catalyst for glycine electrosynthesis. Notably, a record-low onset potential of −0.09 V versus RHE and an impressive glycine production rate of 1327 µmol h⁻¹ are achieved when using an ultralight Ag foam electrode. This process enables gram-scale glycine production within 20 h and can be widely adapted for synthesizing diverse amino acids. Our findings underscore the vital significance of considering the inherent characteristics of reaction intermediates in catalyst design.

Efficient and long-lasting electrocatalysts are one of the key factors in determining their large-scale commercial viability. Although the fundamentals of deactivation and regeneration of electrocatalysts are crucial for understanding and sustaining durable activity, little has been conducted on metalloids compared to metal-derived ones. Herein, by virtue of in situ seconds-resolved X-ray absorption spectroscopy, we discovered the chemical evolution during the deactivation-regeneration cycles of tellurium clusters supported by nitrogen-doped carbon (termed Te-ACs@NC) as a high-performance electrocatalyst in the hydrogen evolution reaction (HER). Through in situ electrochemical reduction, Te-ACs@NC, which had been deactivated due to surface phase transitions in a previous HER process, was reactivated and regenerated for the next run, where partially oxidized Te was found, surprisingly, to perform better than its nonoxidized state. After 10 consecutive deactivation-regeneration cycles over 480 h, the Te-ACs@NC retained 85% of its initial catalytic activity. Theoretical studies suggest that local oxidation modulates the electronic distribution within individual Te clusters to optimize the adsorption energy of water molecules and reduce dissociation energy. This study provides fundamental insights into the rarely explored metalloid cluster catalysts during deactivation and regeneration and will assist in the future design and development of supported catalysts with high activity and long durability.

3D printing as an advanced manufacturing technique provides an alternative cost-effective option for design and preparation of porous catalytic electrodes. Herein, carbonaceous catalytic electrodes with ternary dopants of boron (B), phosphorous (P), and nitrogen (N) (termed BPN-3Dp-CCEs) were successfully engineered via combination of the 3D printing technique and the following conformal carbonization of ionic liquid. The as-made electrodes were in turn applied to electrify CO₂ into syngas in a controllable composition of a H₂:CO molar ratio of 0.32–3.46. Notably, the BPN-3Dp-CCEs have tailored 3D macroscopic shapes of self-supporting skeletons, and due to ternary doping, demonstrated promoted catalytic activity in the electrocatalytic CO₂ conversion into syngas. Upon optimization, the electrode remained stable in structure and performance after 10 h of a continuous CO₂ electrolysis operation. This study casts insights and fuels the continuous exploration of multi-heteroatoms doped porous carbon electrodes for metal-free catalytic applications.

Actuators based on electrically conductive and hydrophilic two-dimensional (2D) Ti₃C₂T_X MXene are of interest for fast and specific responses in demanding environments, such as chemical production. Herein, Ti₃C₂T_X-based solvent-responsive bilayer actuators were developed, featuring a gradient polymer-intercalation structure in the active layer. These actuators were assembled using negatively charged pristine Ti₃C₂T_X nanosheets as the passive layer and positively charged polymer-tethered Ti₃C₂T_X as the active layer. 2D wide-angle X-ray scattering and simulations related the gradient polymer intercalated microstructure in the polymer/MXene composite active layer to the counterintuitive actuation behavior. The bending of the bilayer films in solvent vapor is triggered by the gradient polymer-intercalation and the differing diffusion rate of solvent molecules through the MX and MX-polymer layers of the bilayer actuator. With their ease of fabrication, remote light-control capabilities, and excellent actuation performance, the Ti₃C₂T_X-based bilayer actuators reported here may find applications in areas such as sensors for monitoring chemical production, infrared camouflage, smart switches, and excavators in toxic solvent environments.

Solvent-free ion-conducting elastomers exhibit distinct advantages over hydrogels and ionogels such as zero solvent leakage and high electrochemical stability. However, achieving simultaneous enhancements in both mechanical and ion-conducting properties remains a challenge due to the inherent trade-off in these properties. To overcome this trade-off, we prepared solvent-free ionic elastomers with favorable ionic conductivity and mechanical properties by incorporating MXene into ion-conductive poly(ionic liquid) networks. The elastomers with a suitable MXene content demonstrated a high ionic conductivity of 0.044 S/m at 30 °C and a tensile strength of 0.48 MPa. Structural analysis attributed the enhanced tensile strength to the nanofiller effect of MXene that electrostatically interacts with the poly(ionic liquid) matrix. Dielectric spectroscopy revealed that the addition of MXene facilitates extra pathways for ion transport, thereby improving the ionic conductivity. The solvent-free MXene/poly(ionic liquid) elastomers were utilized as strain sensors and photothermal materials, demonstrating potential applications for personal management and photothermal therapy.

The true promise of MXene as a practical supercapacitor electrode hinges on the simultaneous advancement of its three-dimensional (3D) assembly and the engineering of its nanoscopic architecture, two critical factors for facilitating mass transport and enhancing an electrode’s charge-storage performance. Herein, we present a straightforward strategy to engineer robust 3D freestanding MXene (Ti₃C₂T_x) hydrogels with hierarchically porous structures. The tetraamminezinc(II) complex cation ([Zn(NH₃)₄]²⁺) is selected to electrostatically assemble colloidal MXene nanosheets into a 3D interconnected hydrogel framework, followed by a mild oxidative acid-etching process to create nanoholes on the MXene surface. These hierarchically porous, conductive holey-MXene frameworks facilitate 3D transport of both electrons and electrolyte ions to deliver an excellent specific capacitance of 359.2 F g^–1 at 10 mV s^–1 and superb capacitance retention of 79% at 5000 mV s^–1, representing a 42.2% and 15.3% improvement over pristine MXene hydrogel, respectively. Even at a commercial-standard mass loading of 10.1 mg cm^–2, it maintains an impressive capacitance retention of 52% at 1000 mV s^–1. This rational design of an electrode by engineering nanoholes on MXene nanosheets within a 3D porous framework dictates a significant step forward toward the practical use of MXene and other 2D materials in electrochemical energy storage systems. 

Given the abundant solar light available on our planet, it is promising to develop an advanced fabric capable of simultaneously providing personal thermal management and facilitating clean water production in an energy-efficient manner. In this study, we present the fabrication of a photothermally active, biodegradable composite cloth composed of titanium carbide MXene and cellulose, achieved through an electrospinning method. This composite cloth exhibits favorable attributes, including chemical stability, mechanical performance, structural flexibility, and wettability. Notably, our 0.1-mm-thick composite cloth (RC/MXene IV) raises the temperature of simulated skin by 5.6 degrees C when compared to a commercially available cotton cloth, which is five times thicker under identical ambient conditions. Remarkably, the composite cloth (RC/MXene V) demonstrates heightened solar light capture efficiency (87.7%) when in a wet state instead of a dry state. Consequently, this cloth functions exceptionally well as a high-performance steam generator, boasting a superior water evaporation rate of 1.34 kg m(-2) h(-1) under one-sun irradiation (equivalent to 1000 W m(-2)). Moreover, it maintains its performance excellence in solar desalination processes. The multifunctionality of these cloths opens doors to a diverse array of outdoor applications, including solar-driven water evaporation and personal heating, thereby enriching the scope of integrated functionalities for textiles.

Understanding the reconstruction of surface sites is crucial for gaining insights into the true active sites and catalytic mechanisms. While extensive research has been conducted on reconstruction behaviors of atomically dispersed metallic catalytic sites, limited attention has been paid to non-metallic ones despite their potential catalytic activity comparable or even superior to their noble-metal counterpart. Herein, we report a carbonaceous, atomically dispersed non-metallic selenium catalyst that displayed exceptional catalytic activity in the hydrazine oxidation reaction (HzOR) in alkaline media, outperforming the noble-metal Pt catalysts. In situ X-ray absorption spectroscopy (XAS) and Fourier transform infrared spectroscopy revealed that the pristine SeC₄ site pre-adsorbs an ∗OH ligand, followed by HzOR occurring on the other side of the OH–SeC₄. Theoretical calculations proposed that the pre-adsorbed ∗OH group pulls electrons from the Se site, resulting in a more positively charged Se and a higher polarity of Se–C bonds, thereby enhancing surface reactivity toward HzO/R.