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Seawater hydrogen production, vital for sustainable energy solutions and freshwater preservation, faces challenges due to seawater complexity and high energy consumption. A strategy to modulate dehydrogenation kinetics of dual‐phase metal nitrides using low‐loaded Pt quantum dots (QDs), achieving stable and energy‐efficient hydrogen generation is introduced. The Pt QDs@Ni3N‐MoN/Ti catalyst displays outstanding bifunctional seawater catalytic performance, enabling efficient hydrogen production and hydrazine degradation in a flow anion exchange membrane water electrolysis (AEMWE) device. Operating at a low voltage of 1.41 V, it achieves 2 A cm−2 for 300 h, circumventing chlorine corrosion and yielding record‐breaking energy equivalent input (2.68 kWh m−3 H2 at 1 A cm−2), a 47.1% reduction compared to traditional methods. Integration with solar and biomass energy facilitates self‐powered hybrid seawater hydrogen production, highlighting its potential applications. This work facilitates energy‐efficient marine resource conversion to green hydrogen and offers viable insights into industrial hazardous pollutant degradation using metal‐nitride electrocatalysts. [ABSTRACT FROM AUTHOR]

Seawater hydrogen production, vital for sustainable energy solutions and freshwater preservation, faces challenges due to seawater complexity and high energy consumption. A strategy to modulate dehydrogenation kinetics of dual‐phase metal nitrides using low‐loaded Pt quantum dots (QDs), achieving stable and energy‐efficient hydrogen generation is introduced. The Pt QDs@Ni3N‐MoN/Ti catalyst displays outstanding bifunctional seawater catalytic performance, enabling efficient hydrogen production and hydrazine degradation in a flow anion exchange membrane water electrolysis (AEMWE) device. Operating at a low voltage of 1.41 V, it achieves 2 A cm−2 for 300 h, circumventing chlorine corrosion and yielding record‐breaking energy equivalent input (2.68 kWh m−3 H2 at 1 A cm−2), a 47.1% reduction compared to traditional methods. Integration with solar and biomass energy facilitates self‐powered hybrid seawater hydrogen production, highlighting its potential applications. This work facilitates energy‐efficient marine resource conversion to green hydrogen and offers viable insights into industrial hazardous pollutant degradation using metal‐nitride electrocatalysts. [ABSTRACT FROM AUTHOR]

Electrolysis of seawater represents great potentials for sustainable hydrogen production. However, both competitive Cl− adsorption and catalysts corrosion caused by chlorine oxidation reaction (ClOR) are major challenges in seawater electrolysis. Inspired by the concept of hard and soft acids and bases (HSAB), polyphosphate oxyanions (P3O105−) on Ni(OH)2 surface is coordinated to obtain harder acid Ni sites, which could obtain 160 times stability enhancement compared to pure Ni(OH)2 for oxygen evolution reaction (OER) in alkaline seawater at 800 mA cm−2. Also, the turnover frequency value on Ni(OH)2‐P3O105− is 50 times that on Ni(OH)2, implying higher intrinsic OER activity of Ni(OH)2‐P3O105−. Theoretical and experimental investigations show that P3O105− could facilitate transition of Ni3+ to harder acid Ni>3+, thus preferring adsorption of hard base OH− rather than soft base Cl−. This could enhance OER selectivity and inhibit undesirable ClOR. Furthermore, molecular dynamics simulations indicate that the Cl− concentration near the electrode could be reduced by nearly half due to electrostatic repulsion of Cl− by surface P3O105− oxyanions. When assembled into an electrolyzer for alkaline seawater splitting, it could operate at 2.2 V with large current up to 1.4 A for 240 h. [ABSTRACT FROM AUTHOR]

The development of high‐purity and high‐energy‐density green hydrogen through water electrolysis holds immense promise, but issues such as electrocatalyst costs and power consumption have hampered its practical application. In this study, we present a promising solution to these challenges through the use of a high‐performance bifunctional electrocatalyst for energy‐efficient hydrogen production via coupled hydrazine degradation. The biphasic metal nitrides with highly lattice‐matched structures are deliberately constructed, forming an enhanced local electric field between the electron‐rich Ni3N and electron‐deficient Co3N. Additionally, Mn is introduced as an electric field engine to further activate electron redistribution. Our Mn@Ni3N‐Co3N/NF bifunctional electrocatalyst achieves industrial‐grade current densities of 500 mA cm−2 at 0.49 V without degradation, saving at least 53.3 % energy consumption compared to conventional alkaline water electrolysis. This work will stimulate the further development of metal nitride electrocatalysts and also provide new perspectives on low‐cost hydrogen production and environmental protection. [ABSTRACT FROM AUTHOR]

Detecting H 2 S in oxygen-deficient conditions is vital for identifying leaks in SF 6 -insulated electrical equipment. Current infrared-based detection methods are expensive and sensitive to environmental conditions, highlighting the necessity for cost-effective and stable gas sensors. Existing gas sensors based on semiconducting metal oxides (SMOXs) are limited by redox reactions with oxygen and require high operating temperatures. Here, we introduce a room-temperature (RT) H 2 S sensor for oxygen-deficient environments using the intrinsic conducting two-dimensional (2D) metal-organic framework (MOF), Co 1.8 Ni 1.2 (hexaiminotriphenylene) 2 [Co 1.8 Ni 1.2 (HITP) 2 ], overcoming the limitations of SMOX gas sensors. Remarkably, Co 1.8 Ni 1.2 (HITP) 2 sensors exhibit exceptional selectivity for H 2 S with negligible cross-responses and a sensitivity drift of less than 4.13% in an SF 6 atmosphere over 60 days. The Co 1.8 Ni 1.2 (HITP) 2 gas sensor shows significant promise for real-time and stable monitoring of H 2 S gas in oxygen-deficient environments.

Nitrogen dioxide (NO 2 ) is a significant environmental and human health hazard. Current NO 2 sensors often lack sensitivity and selectivity under ambient conditions. This study investigates ammonia pyrolysis modification of monolayer Ti 3 C 2 T x MXene to enhance NO 2 detection at room temperature. Nitrogen-doped Ti 3 C 2 T x demonstrates a substantial improvement in sensitivity, with a response of 8.87% to 50 ppm of NO 2 compared to 0.65% for the original sensor, representing a 13.8-fold increase. The nitrogen-doped sensor also exhibits superior selectivity and linearity for NO 2 under ambient conditions. Theoretical analysis shows that nitrogen incorporation promotes enhanced interaction between Ti 3 C 2 T x and its surface oxygen-containing functional groups through electronic hybridization, resulting in improved adsorption energy (1.80 |eV|) and electron transfer efficiency (0.67 |e|) for NO 2 , thereby enhancing its gas-sensing performance. This study highlights the potential of ammonia pyrolysis-treated Ti 3 C 2 T x MXene for advancing NO 2 sensor technologies with heightened performance at room temperature.

Strategies for discovery of high-performance electrocatalysts are important to advance clean energy technologies. Metastable phases such as low temperature or interfacial structures that are difficult to access in bulk may offer such catalytically active surfaces. We report here that the suboxide Zr 3 O, which is formed at Zr-ZrO 2 interfaces but does not appear in the experimental Zr-O phase diagram exhibits outstanding oxygen reduction reaction (ORR) performance surpassing that of benchmark Pt/C and most transition metal-based catalysts. Addition of Fe 3 C nanoparticles to give a Zr-Zr 3 O-Fe 3 C/NC catalyst (NC=nitrogen-doped carbon) gives a half-wave potential (E 1/2 ) of 0.914 V, outperforming Pt/C and showing only a 3 mV decrease after 20,000 electrochemical cycles. A zinc-air battery (ZAB) using this cathode material has a high power density of 241.1 mW cm -2 and remains stable for over 50 days of continuous cycling, demonstrating potential for practical applications. Zr 3 O demonstrates that interfacial or other phases that are difficult to stabilize may offer new directions for the discovery of high-performance electrocatalysts., (© 2024 Wiley-VCH GmbH.)

The ocean, a vast hydrogen reservoir, holds potential for sustainable energy and water development. Developing high-performance electrocatalysts for hydrogen production under harsh seawater conditions is challenging. Here, we propose incorporating a protective V 2 O 3 layer to modulate the microcatalytic environment and create in situ dual-active sites consisting of low-loaded Pt and Ni 3 N. This catalyst demonstrates an ultralow overpotential of 80 mV at 500 mA cm -2 , a mass activity 30.86 times higher than Pt-C and maintains at least 500 hours in seawater. Moreover, the assembled anion exchange membrane water electrolyzers (AEMWE) demonstrate superior activity and durability even under demanding industrial conditions. In situ localized pH analysis elucidates the microcatalytic environmental regulation mechanism of the V 2 O 3 layer. Its role as a Lewis acid layer enables the sequestration of excess OH - ions, mitigate Cl - corrosion, and alkaline earth salt precipitation. Our catalyst protection strategy by using V 2 O 3 presents a promising and cost-effective approach for large-scale sustainable green hydrogen production.

The development of high-purity and high-energy-density green hydrogen through water electrolysis holds immense promise, but issues such as electrocatalyst costs and power consumption have hampered its practical application. In this study, we present a promising solution to these challenges through the use of a high-performance bifunctional electrocatalyst for energy-efficient hydrogen production via coupled hydrazine degradation. The biphasic metal nitrides with highly lattice-matched structures are deliberately constructed, forming an enhanced local electric field between the electron-rich Ni 3 N and electron-deficient Co 3 N. Additionally, Mn is introduced as an electric field engine to further activate electron redistribution. Our Mn@Ni 3 N-Co 3 N/NF bifunctional electrocatalyst achieves industrial-grade current densities of 500 mA cm -2 at 0.49 V without degradation, saving at least 53.3 % energy consumption compared to conventional alkaline water electrolysis. This work will stimulate the further development of metal nitride electrocatalysts and also provide new perspectives on low-cost hydrogen production and environmental protection., (© 2024 Wiley‐VCH GmbH.)

Fuel cell gas sensors have emerged as promising advanced sensing devices owing to their advantageous features of low power consumption and cost-effectiveness. However, commercially available Pt/C electrodes pose significant challenges in terms of stability and accurate detection of low concentrations of target gases. Here, we introduce an efficient Cu-Pt/CrN-based fuel cell gas sensor, designed specifically for the ultrasensitive detection of hydrogen sulfide (H 2 S) at room temperature. Compared to the commercial Pt/C sensor, the Cu-Pt/CrN sensor exhibits excellent sensitivity (0.26 μA/ppm), with an increase in the selectivity by a factor of 2.5, and demonstrates good stability over a 2 month period. The enhanced sensing performance can be attributed to the modulation of the electronic arrangement of Pt by Cu, resulting in an augmentation of H 2 S adsorption. The Cu-Pt/CrN fuel cell gas sensor provides an opportunity for detecting parts per billion-level H 2 S in various applications.