SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3757-2
β-Ga2O3 is a promising candidate for solar-blind ultraviolet photodetection owing to its suitable bandgap of approximately 4.9 eV, excellent photoresponse characteristics, and high stability. However, the lack of a sufficient driving force within the material leads to extensive bulk charge recombination, limiting its photocurrent and thus posing significant challenges in designing high-performance Ga2O3-based photodetection. In this study, we propose a gradient doping strategy to achieve a Sn-doping concentration gradient along the β-Ga2O3 film thickness. By combining sol–gel synthesis with rapid thermal annealing, a spatially graded band structure with a full-space built-in electric field is constructed, which increases the width of band bending over a large region and is crucial for significantly enhancing carrier separation and transport in the bulk. The resulting gradient Sn-doped β-Ga2O3 enables exceptional photoelectric performance without an external bias under 254 nm irradiation, including a superior responsivity of 66.88 mA W−1, a high detectivity of 8.12 × 10^11 Jones, and a fast rise/decay time of 79/65 ms, outstanding most existing similar reported photoelectrochemical (PEC) type optoelectronic devices. Additionally, the device exhibits excellent long-term stability and enables high-resolution underwater ultraviolet imaging. This study demonstrates that the gradient doping strategy provides a feasible approach for enhancing the PEC performance of β-Ga2O3 photoelectrodes.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202604014
Ice slurry pigging is an emerging technology for cleaning water supply pipelines, yet quantitative understanding of its cleaning mechanisms and optimal operating conditions remains limited. This study developed a computational fluid dynamics (CFD) model integrating the kinetic theory of granular flows (KTGF), the Euler-Euler method, and the shear stress transport (SST) model to simulate ice slurry flow and wall shear stress distribution. The model was validated against experimental data, showing a 6.4% error in particle concentration distribution, a 3.3% average error in solid-phase velocity in the mainstream region, and a pressure drop error within 20%. A total of 125 simulations were performed under varying initial concentrations (20%–60%), particle diameters (0.3–1.0 mm), and flow velocities (0.2–1.0 m/s). Results indicate that higher initial concentrations (60%) achieve effective cleaning of both upper and lower pipe walls, with an effective shear stress ratio of 77.39%. Larger particles exhibit pronounced upward movement, increasing non-uniformity in solid distribution. Flow velocity is the dominant factor affecting wall shear stress; at 1.0 m/s, the effective shear stress ratio reaches 83.16%. The optimal parameters for cumulative shear stress were identified as 50% initial concentration, 0.5 mm particle diameter, and 1.0 m/s flow velocity, yielding an average cumulative shear stress of 11.59 Pa·s. For effective cumulative shear stress, the same parameters produced 9.89 Pa·s, while the highest effective shear stress ratio (88.50%) was achieved with 0.3 mm particles at 1.0 m/s and 50% concentration. This research provides theoretical guidance for ice slurry pigging operations in water supply pipelines.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3892-2
Single-atom co-catalysts on semiconductor substrates offer a cost-efficient route to enhance photocatalytic performance with minimal precious metal loading. However, precise tuning of local coordination environments and construction of efficient single-atom co-catalysts remain challenging for overall water splitting. Here, we employ an icing-assisted photochemical reduction strategy to anchor atomically dispersed Pt species as hydrogen evolution co-catalysts on Al3+-doped SrTiO3 (Pt SA-STO). The optimized Pt SA-STO exhibits remarkable activity, with hydrogen and oxygen evolution rates of 13.62 and 6.71 mmol h−1 g−1, respectively, and a turnover frequency (TOF) of 2114.5 h−1. We pioneer the use of nuclear magnetic resonance (NMR) spectroscopy to quantitatively track the temporal evolution of Pt4+ to Pt2+ under continuous irradiation during the icing-assisted photoreduction. Advanced characterizations and theoretical calculations confirm that single-atom Pt co-catalysts facilitate directional transfer and extraction of photogenerated charge carriers, effectively suppressing surface recombination. This work provides insights into designing novel single-atom co-catalysts by deepening understanding of electronic configurations and active sites in photocatalytic overall water splitting.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4282-y
Recovering gold from electronic waste (e-waste) is critical for sustainable resource management, yet conventional adsorbents suffer from poor acid stability and slow kinetics. Here, we report an acid-resistant cationic covalent organic framework (COF), TAPT-TNV, synthesized via irreversible Zincke reaction. TAPT-TNV exhibits exceptional stability in concentrated acids, retaining crystallinity and porosity after exposure to 12 M HCl and 6 M HNO3. The cationic skeleton, balanced by Cl− counterions, enables rapid and selective capture of AuCl4− through anion exchange, complemented by chemical reduction at triazine units. Adsorption kinetics are fast, reaching equilibrium within 30 minutes, with a maximum capacity of 1835.5 mg g−1 at pH 1. In real e-waste leachate, TAPT-TNV achieves a gold recovery rate of 99.42%, demonstrating high selectivity over competing metal ions. This work introduces a robust COF platform for precious metal recovery, addressing the limitations of hydrolytically unstable frameworks.