reformed hydrogen as feedstock under harsh conditions. [3] Ambient electrocatalytic N 2 reduction reaction (NRR) has emerged as an attractive alternative for NH 3 production, which however suffers from unsatisfactory Faradaic efficiencies (FE) (mostly <50%) and very low NH 3 partial current densities (mostly <1 mA cm -2 ) due to extremely stable triple NN bond (941 kJ mol -1 ) and low N 2 solubility. [4,5] Nitrate reduction into NH 3 (NO 3 -RR) is considered as a promising alternative with large attainable yields owing to the high solubility of NO 3 and low NO bond energy (204 kJ mol -1 ). [6] Furthermore, NO 3 is one of the most widespread groundwater pollutants in the world due to the discharge of industrial wastewater, livestock excrements, and chemical fertilizers, imposing a threat to the health of human beings. [7] Therefore, it is highly attractive to harness NO 3 contaminants to produce the value-added NH 3 from the energy and environmental perspectives.In addition to the chemicals, electricity is one other key pillar of human society. [8][9][10][11][12][13][14][15][16] Notably, the NO 3 -RR involves proton-assisted eightelectron transfer process and its equilibrium potential is 0.69 V versus the reversible hydrogen electrode (RHE), higher than the 0.4 V of the oxygen reduction reaction in Zn-air/oxygen batteries. [17] It is thus highly attractive to combine the NO 3 -RRbased cathode with metal anode as a galvanic cell for electricity production. Such metal-NO 3 battery as a "killing three birds with one stone" strategy is capable of energy supply, ammonia production, and removal of pollutant in ground water. As some possible byproducts such as nitrite and hydrazine may lower the efficiency of such battery, catalyst cathodes with high NH 3 selectivity is highly desired for practical use. [18][19][20] First row transition metal phosphides, as alloy materials of metal and phosphorus, are active catalysts in hydrotreating (HDX, X = S, O, N) and hydrogenation reactions. [21,22] The metal centers in phosphides with partial positive charge can adsorb nitrate and nitrite anions effectively while the partial negative charge centers, i.e., phosphorus, are the proton-acceptor centers. [23] Further, heteroatom doping can well modulate the electronic structure of the catalyst and boost the catalytic activity. [24] The The electrocatalytic nitrate reduction reaction (NO 3 -RR) to ammonia (NH 3 ) offers a promising alternative approach for NH 3 production and nitratebased voltaic cells which can deliver both electricity and NH 3 as products, are also highly attractive. However, nitrate-to-NH 3 conversion involves a proton-assisted multiple-electron transfer process with considerable kinetic barrier, underlying the need for efficient catalysts for the NO 3 -RR. A Zn-nitrate battery is reported to enable a "killing three birds with one stone" strategy for energy supply, ammonia production and removal of pollutants with the iron doped nickel phosphide (Fe/Ni 2 P) as a NO 3 -RR catalyst electrode. Iron doping induces a d...

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The incapability of modulating the photoresponse of assembled heterostructure devices has remained a challenge for the development of optoelectronics with multifunctionality. Here, a gatetunable and anti-ambipolar phototransistor is reported based on 1D GaAsSb nanowire/2D MoS 2 nanoflake mixed-dimensional van der Waals heterojunctions. The resulting heterojunction shows apparently asymmetric control over the anti-ambipolar transfer characteristics, possessing potential to implement electronic functions in logic circuits. Meanwhile, such an anti-ambipolar device allows the synchronous adjustment of band slope and depletion regions by gating in both components, thereby giving rise to the gate-tunability of the photoresponse. Coupled with the synergistic effect of the materials in different dimensionality, the hybrid heterojunction can be readily modulated by the external gate to achieve a highperformance photodetector exhibiting a large on/off current ratio of 4 × 10 4 , fast response of 50 μs, and high detectivity of 1.64 × 10 11 Jones. Due to the formation of type-II band alignment and strong interfacial coupling, a prominent photovoltaic response is explored in the heterojunction as well. Finally, a visible image sensor based on this hybrid device is demonstrated with good imaging capability, suggesting the promising application prospect in future optoelectronic systems.

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Surface self-reconstruction processes in alkaline hydrogen evolution reaction (HER), especially regarding the explicit structure-activity relationships, remain elusive. Here, we first design a hierarchical Co@NCNT/CoMoOx precatalyst constituted by the defective CoMoOx...

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Design of efficient and robust electrocatalysts for hydrogen evolution reaction (HER) under all pH conditions has attracted significant attention. In particular, it is still a considerable challenge since the HER kinetics of Pt in alkaline solutions is about two to three orders of magnitude lower than that in acidic conditions. Herein, a heterogeneous yolk–shell nanostructure with Rh nanoparticles embedded in S, N co‐doped carbon nanospheres prepared by a facile self‐template method is reported. The optimized electrocatalyst can achieve an extremely small overpotential of 13.5 mV at 10 mA cm‐2, low Tafel slope of 25.5 mV dec‐1, high turnover frequency of 0.143 s‐1 (at −75 mV vs. reversible hydrogen electrode), and long‐term durability for 10 h, which is the record‐high alkaline HER activity among the ever‐reported noble metal based catalysts. These striking performances are ascribed to the optimized electronic structure and unique heterogeneous yolk–shell nanostructure. More importantly, it is also demonstrated that the obtained electrocatalyst exhibits superior activities in all pH range, which is better than commercial Pt/C and Rh/C catalysts. This work proves that Rh‐based nanomaterials are promising superior electrocatalysts in a wide pH range and nanostructure design is a powerful tool to increase the mass/electron transfer during reaction.

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