La掺杂的TiO_2纳米棒在常温常压下可促进电催化的N_2转化为NH_3（英文）

氨在化肥、染料、药品和炸药的制造中起着重要作用.目前,传统的Haber-Bosch工艺主要用于NH_3的大规模工业化生产,在苛刻的反应条件(300～500℃,150～300 atm)下不可避免地伴随着温室气体的过量排放.因此,必须寻求一种绿色并且可持续的方法来生产NH_3.电化学还原N_2 (NRR)已成为在环境条件下将N_2连续固定NH_3的一种有吸引力的替代方法.由于稳定的N≡N具有较强的偶极矩并与析氢反应存在激烈竞争,因此需要高效的NRR催化剂.TiO_2是典型的n型半导体,被认为是一种很有前途的NRR电催化剂.最近的研究表明,La_2O_3对N_2还原电催化也具有活性,然而镧金属的稀土性质限制了其大规模应用.本文研究发现镧可以作为一种有效的掺杂剂提高TiO_2的NRR活性.通过水热法制备了镧掺杂的TiO_2纳米棒(La-TiO_2).透射电子显微镜结果表明,原始TiO_2与La-TiO_2在形貌上都是纳米棒,镧的引入对其形貌并没有显著影响.选区电子衍射证实了La-TiO_2纳米棒的高结晶度和四边形单晶结构.电子自旋共振分析结果表明La-TiO_2纳米棒中存在氧空位.La-TiO_2的线性扫描伏安曲线结果表明,在N_2饱和电解液中的电流密度明显大于在Ar饱和电解液中,说明NRR的发生.为了进一步证实这一假设,在五个不同电位下分别进行了一系列的计时电流测试,结果表明,连续电解2 h后在-0.70 V时,NH_3产率最高,达23.06mg h~(-1) mg~(-1)_(cat),并且法拉第效率也最大,达14.54%.此外,电解2 h后,没有检测到副产物N_2H_4,表明La-TiO_2催化剂对NH_3合成具有良好的选择性.本文还比较了La-TiO_2/CP,TiO_2/CP和CP的NRR电催化性能,结果表明,La-TiO_2/CP的NH_3产率最高,说明La的引入提高了La-TiO_2的NRR活性.La-TiO_2/CP通过在-0.70 V下连续6次循环测试以及连续48 h电解测试证实La-TiO_2对NRR电催化具有良好的电化学稳定性.通过对La-O_v构型进行密度泛函理论计算,重点研究*N_2+H~++e~-→*NNH的反应步骤,由于*N_2加氢的自由能垒较低,La-TiO_2更容易激活N_2分子,计算了La-TiO_2和纯TiO_2上*NNH中间体的电荷密度差异,*NNH与La-TiO_2之间存在更多的电荷转移.采用N–N键的积分晶体轨道哈密顿布居(ICOHP)分析出La-TiO_2的ICOHP负值较小(-16.67 vs.-19.93),说明N–N键的活化更多.     

阴离子改性甘油溶液中TiO2纳米管阵列的制备和表征

本文采用电化学阳极氧化法以含氟的甘油和水混合溶液为电解液在纯钛表面制备了一层排列规整的TiO2纳米管阵列,研究了电解液中额外添加3种2价阴离子、不同的电解时间及不同的添加物浓度等因素对所获得的TiO2纳米管阵列形貌的影响。结果表明,在改性电解液中制备的TiO2纳米管阵列的长度均超过了未改性的电解液中制备的,并随着氧化时间的增长,纳米管管口直径增大,管壁变薄;同时添加的(NH4)2TiF6浓度在0.025~0.1 mol.L-1范围内均可获得管长更长且形貌较好的TiO2纳米管阵列。     

镧掺杂纳米TiO2应用助剂筛选及其对农药残留的光催化降解效果

通过润湿分散剂(十二烷基苯磺酸钠ABS-Na、木质素磺酸钠SL和羧甲基纤维素钠CMC)和载体(白炭黑、高岭土)的筛选,确定了60%稀土镧掺杂纳米TiO2可湿性粉剂(WP)的最优配方。试验结果表明:十二烷基苯磺酸钠为2%,木质素磺酸钠6%,采用高岭土作载体,可湿性粉剂的悬浮率达到了98.12%,润湿时间为4.09 s,且冷贮、热贮合格。通过克百威溶液在太阳光下的消失情况来研究La-TiO2可湿性粉剂的光催化降解效果。试验表明:稀土镧掺杂后的纳米TiO2光催化活性得到了提高,且使用La-TiO2可湿性粉剂能进一步提高克百威的光催化降解效果,当降解效果达最大时,La-TiO2最佳用量为0.2 g.L-1,而直接使用La-TiO2粉末,其最佳用量为0.4 g.L-1。     

N掺杂富含(001)晶面TiO_2纳米片的制备及N掺杂浓度对可见光催化活性的影响(英文)

采用水热法制备了富含(001)晶面的锐钛矿型TiO2纳米片,并通过改变热处理过程中NH3流速制备不同N掺杂浓度的TiO2纳米片.运用X射线衍射、场发射扫描电镜、高分辨率透射电子显微镜、紫外-可见漫反射光谱、X射线光电子能谱和荧光光谱对光催化剂进行了结构和性能表征,并以罗丹明B为目标降解物,考察了N掺杂浓度对TiO2纳米片可见光催化活性的影响.结果表明,NH3流速为40ml/min时制备的N掺杂TiO2纳米片具有最低的光生电子-空穴复合速率,最高的OH产生能力并表现出最高的光催化活性.同时,讨论了N掺杂浓度对TiO纳米片可见光催化活性影响的机理.     

纳米SnO2/TiO2电极的制备及其电催化降解间-硝基苯酚

用电化学方法在乙二醇溶液中制备锡、钛醇盐配合物Sn0.75Ti(OCH2CH2OH)(7-x),将电解液水解、干燥后在400℃煅烧2 h,得到纳米级SnO2/TiO2粉体。通过红外光谱(FT-IR)和拉曼光谱(Raman)对电解产物进行测试,纳米SnO2/TiO2粉体通过X射线粉末衍射(XRD)和扫描电子显微镜(SEM)进行表征。实验表明,在有机体系电解得到的纳米SnO2/TiO2粉体颗粒分散较理想,粒径在100～200 nm。再通过溶胶-凝胶法在钛丝表面得到纳米SnO2/TiO2电极,采用循环伏安法研究电极在酸性溶液和间-硝基苯酚溶液中的氧化还原行为和电催化活性。结果表明,纳米TiO2掺杂SnO2电极的氧化峰电流达到143×10-3A/cm2,氧化还原峰电位差明显减小,催化降解间-硝基苯酚的COD去除率达到86.1%,具有较高的电催化活性。     

TiO2纳米棒载Pd催化剂的制备及其对甲酸的电催化氧化

利用水热合成和无机溶胶法,分别制备了具有棒状(TiO2-R)和无规则结构(TiO2-I)的锐钛矿相TiO2,并以之为载体制备得到Pd/TiO2电催化剂.循环伏安测试显示,与无规则TiO2相比,具有棒状结构的TiO2载Pd催化剂对甲酸氧化的电催化性能提高了70%;计时电流测试显示,运行3000 s后,甲酸在棒状TiO2载Pd催化剂上的氧化电流是无规则TiO2载Pd催化剂的16倍.其原因可能与TiO2纳米棒拥有更好的电子传导性且表面拥有较多的活性含氧基团有关,从而能够有效提高催化剂对甲酸氧化的电催化活性和抗毒化性能.     

RuO_2/TiO_2纳米薄膜的新构建及对CO_2的电催化还原

在旋涂有球状纳米TiO2薄膜的导电玻璃(ITO)基底上采用循环伏安法(CV)电沉积RuO2作为电催化还原CO2的阴极.采用场发射扫描电子显微镜(FE-SEM)表征了RuO2/TiO2纳米薄膜的形貌,并应用近稳态电位扫描法和计时电流法(i～t)研究了薄膜的电催化CO2性能.结果表明所构建的RuO2/TiO2薄膜中纳米粒子大小均匀、排列致密,且较传统热分解法所得催化剂有更好的电催化性能.     

磁载纳米TiO2光催化剂的制备及其光催化性能研究

采用肼((NH2)2*H2O)还原硝酸铁(Fe(NO3)3)法制备纳米级磁基体(Fe3O4), 以聚乙二醇对其表面进行改性, 通过溶胶-凝胶法制得TiO2/Fe3O4磁载纳米TiO2光催化剂, 并用于光催化降解橙黄-II, 对其活性进行评价. 结果表明 TiO2/Fe3O4光催化剂的降解率在第一次使用时与纯TiO2相近, 三次循环使用后, 仍能保持较高的催化活性. 催化剂的最佳用量为4 g/L, 在酸性和碱性环境中均能保持很好的催化活性.     

氮还原反应中氨定量假阳性结果的来源与消除方法（英文）

氨(NH3)广泛应用于化肥等工业化学品的生产中,年消耗量巨大.同时,氨具有高氢含量和高能量密度,可作为清洁能源载体和燃料,具有广阔的应用前景.因此,合成氨工业在国民经济和社会发展中起着重要作用.目前,合成氨的主要采用传统的Haber-Bosch工艺,但其严苛的操作条件导致了大量能源消耗和二氧化碳排放,进一步加剧了全球变暖.在全球能源危机和环境问题的背景下,开发可再生能源驱动的绿色高效氨合成技术受到广泛关注.其中,以光催化和电催化为动力的氮还原反应(NRR)被认为是最有前途的方法之一.然而,由于N2吸附动力学缓慢, N≡N键分裂困难且析氢反应严重,目前电催化和光催化氮还原的产率和法拉第效率都较低.近年来,得益于各种催化剂和电解液的发展, NRR产率和法拉第效率不断提升,但也逐渐暴露出一些严重的问题——测试结果呈现高波动性和低重复性,甚至假阳性,这使得人们对NRR的发展前景产生了怀疑.由于NRR反应的产量极低(通常为纳/微摩尔水平),所以反应过程中的微量污染都可能严重影响NH3的定量结果,从而导致对NRR反应体系性能的误判.因此,如何保证得到的产物NH3完全来自于氮气的还原是一个难题.本文...     

La掺杂TiO2负载Pt催化剂制备及其室温氧化低浓度甲醛

甲醛是室内装修污染的重要组分,已严重危害到人们身体健康,在室温条件下消除甲醛引起了人们的广泛兴趣.目前室温清除甲醛主要有物理吸附法、光催化法、等离子体技术及催化氧化技术.物理吸附法主要采用活性炭等作为吸附剂,其初期吸附效果较好,但当吸附饱和之后会重新释放甲醛造成二次污染;光催化法和等离子体技术需要特殊装置,不适合室内室温环境脱除甲醛;而催化氧化技术则可直接将甲醛转化为无毒无害的水和CO2,因而备受关注.Pt/TiO2被认为是目前消除甲醛最有效的催化剂.为进一步降低贵金属Pt的用量及增强其稳定性(Pt被氧化后其活性会降低),本文首次采用稀土La掺杂锐钛矿型TiO2,负载少量Pt后用于室内低浓度(0.5 ppm)甲醛的催化氧化.活性测试结果表明,纯TiO2催化剂上甲醛转化率在5%以下,有可能是物理吸附或可见光催化所致.负载0.5%Pt后,Pt/TiO2和Pt/La-TiO2甲醛转化率均高于80%,尤其是La掺杂活性高达96%以上,且在连续反应8 h甚至延长至40 h后其活性均未见下降趋势.电镜结果表明,La掺杂Pt/La-TiO2催化剂中Pt粒径从未掺杂的2.2 nm降至1.7 nm;CO程序升温脱附测试表明,Pt/La-TiO2/Pt的分散度达66%,而未掺杂样品仅为51%;X射线光电子能谱测试表明,Pt/La-TiO2的表面氧物种高于Pt/TiO2催化剂,说明La掺杂增强了Pt和载体间的相互作用.为探讨Pt/La-TiO2商业化应用前景,将粉体Pt/La-TiO2涂覆在堇青石蜂窝陶瓷上制备成整体催化剂.该整体催化剂在容积为2 m3的密室测试中5 min内即可将浓度为0.5 ppm的甲醛将至0.02 ppm以下.该催化剂在存放3个月后活性略有下降,但在10 min内仍可将甲醛浓度降至0.08 ppm,达到室内甲醛排放标准.综上,本文成功制备了La掺杂Pt/La-TiO2用于室内低浓度甲醛催化氧化,该催化剂表现出优异的催化性能.通过多种表征手段表明,La修饰后贵金属Pt纳米粒子尺寸减小、分散度提高及Pt与载体间相互作用增强是其活性优异的主要原因.以Pt/La-TiO2粉体制备的整体催化剂同样表现出了高的催化性能,具有工业应用前景.     

Synergy of Bi2O3 and RuO2 Nanocatalysts for Low-Overpotential and Wide pH-Window Electrochemical Ammonia Synthesis

Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is still seriously impeded by the inferior NH₃ yield and low Faradaic efficiency, especially at low overpotentials. Herein, we report the synthesis of nano-sized RuO₂ and Bi₂O₃ particles grown on functionalized exfoliated graphene (FEG) through in situ electrodeposition, denoted as RuO₂−Bi₂O₃/FEG. The prepared self-supporting RuO₂−Bi₂O₃/FEG hybrid with a Bi mass loading of 0.70 wt% and Ru mass loading of 0.04 wt% shows excellent NRR performance at low overpotentials in acidic, neutral and alkaline electrolytes. It achieves a large NH₃ yield of 4.58±0.16 μg_NH3 h⁻¹ cm⁻² with a high Faradaic efficiency of 14.6 % at −0.2 V versus reversible hydrogen electrode in 0.1 M Na₂SO₄ electrolyte. This performance benefits from the synergistic effect between Bi₂O₃ and RuO₂ which respectively have a fairly strong interaction of Bi 6p orbitals with the N 2p band and abundant supply of *H, as well as the binder-free characteristic and the convenient electron transfer via graphene nanosheets. This work highlights a new electrocatalyst design strategy that combines transition and main-group metal elements, which may provide some inspirations for designing low-cost and high-performance NRR electrocatalysts in the future.     

非金属电催化剂环境条件下氮还原反应的研究进展

NH₃ plays an important role in modern society as an essential building block in the manufacture of fertilizers, aqueous ammonia, plastics, explosives, and dyes. Additionally, it is regarded as a green alternative fuel, owing to its carbon-free nature, large hydrogen capacity, high energy density, and easy transportation. The Haber-Bosch process plays a dominant role in global NH₃ synthesis; however, it involves high pressure and temperature and employs N₂ and H₂ as feeding gases, thus suffering from high energy consumption and substantial CO₂ emission. As a promising alternative to the Haber-Bosch process, electrochemical N₂ reduction enables sustainable and environmentally benign NH₃ synthesis under ambient conditions. Moreover, its applied potential is compatible with intermittent solar, wind, and other renewable energies. However, efficient electrocatalysts are required to drive N₂-to-NH₃ conversion because of the extremely inert N≡N bond. To date, significant efforts have been made to explore high-performance catalysts with high efficiency and selectivity. Generally, noble-metal catalysts exhibit efficient performance for the NRR, but their scarcity and high cost limit their large-scale application. Therefore, considerable attention has been focused on earth-abundant transition-metal (TM) catalysts that can use empty or unoccupied orbitals to accept the lone-pair electrons of N₂, while donating the abundant d-orbital electrons to the antibonding orbitals of N₂. However, these catalysts may release metal ions, leading to environmental pollution. Most of these TM electrocatalysts may also favor the formation of TM—H bonds, facilitating the hydrogen evolution reaction (HER) during the electrocatalytic reaction. Recent years have seen a surge in the exploration of metal-free catalysts (MFCs). MFCs mainly include carbon-based catalysts (CBCs) and some boron-based and phosphorus-based catalysts. Generally, CBCs exhibit a porous structure and high surface area, which are favorable for exposing more active sites and providing rich accessible channels for mass/electron transfer. Moreover, the Lewis acid sites of most metal-free compounds could accept the lone-pair electron of N₂ and adsorb N₂ molecules by forming nonmetal—N bonds, further widening their potential for electrocatalytic NRR. Compared with metal-based catalysts, the occupied orbitals of metal-free catalysts can only form covalent bonds or conjugated π bonds, hindering electron donation from the electrocatalyst to N₂ and molecular activation. In this review, we summarize the recent progress in the design and development of metal-free electrocatalysts (MFCs) for the ambient NRR, including carbon-based catalysts, boron-based catalysts, and phosphorus-based catalysts. In particular, heteroatom doping (N, O, S, B, P, F, and co-dopants), organic polymers, carbon nitride, and defect engineering are highlighted. We also discuss strategies to boost NRR performance and provide an outlook on the development perspectives of MFCs.     

A Janus Fe-SnO2 Catalyst that Enables Bifunctional Electrochemical Nitrogen Fixation

Electrochemical N₂ reduction reactions (NRR) and the N₂ oxidation reaction (NOR), using H₂O and N₂, are a sustainable approach to N₂ fixation. To date, owing to the chemical inertness of nitrogen, emerging electrocatalysts for the electrochemical NRR and NOR at room temperature and atmospheric pressure remain largely underexplored. Herein, a new-type Fe-SnO₂ was designed as a Janus electrocatalyst for achieving highly efficient NRR and NOR catalysis. A high NH₃ yield of 82.7 μg h⁻¹ mg_cat.⁻¹ and a Faraday efficiency (FE) of 20.4 % were obtained for NRR. This catalyst can also serve as an excellent NOR electrocatalyst with a NO₃⁻ yields of 42.9 μg h⁻¹ mg_cat.⁻¹ and a FE of 0.84 %. By means of experiments and DFT calculations, it is revealed that the oxygen vacancy-anchored single-atom Fe can effectively adsorb and activate chemical inert N₂ molecules, lowering the energy barrier for the vital breakage of N≡N and resulting in the enhanced N₂ fixation performance.     

MoS2‐Based Catalysts for N2 Electroreduction to NH3 – An Overview of MoS2 Optimization Strategies

The nitrogen reduction reaction (NRR) has become an ideal alternative to the Haber‐Bosch process, as NRR possesses, among others, the advantage of operating under ambient conditions and saving energy consumption. The key to efficient NRR is to find a suitable electrocatalyst, which helps to break the strong N≡N bond and improves the reaction selectivity. Molybdenum disulfide (MoS₂) as an emerging layered two‐dimensional material has attracted a mass of attention in various fields. In this minireview, we summarize the optimization strategies of MoS₂‐based catalysts which have been developed to improve the weak NRR activity of primitive MoS₂. Some theoretical predictions have also been summarized, which can provide direction for optimizing NRR activity of future MoS₂‐based materials. Finally, an outlook about the optimization of MoS₂‐based catalysts used in electrochemical N₂ fixation are given.     

Nanoporous Palladium Hydride for Electrocatalytic N2 Reduction under Ambient Conditions

The electrocatalytic nitrogen reduction reaction (NRR) is an alternative eco‐friendly strategy for sustainable N₂ fixation with renewable energy. However, NRR suffers from sluggish kinetics owing to difficult N₂ adsorption and N≡N cleavage. Now, nanoporous palladium hydride is reported as electrocatalyst for electrochemical N₂ reduction under ambient conditions, achieving a high ammonia yield rate of 20.4 μg h^?1 mg^?1 with a Faradaic efficiency of 43.6 % at low overpotential of 150 mV. Isotopic hydrogen labeling studies suggest the involvement of lattice hydrogen atoms in the hydride as active hydrogen source. In situ Raman analysis and density functional theory (DFT) calculations further reveal the reduction of energy barrier for the rate‐limiting *N₂H formation step. The unique protonation mode of palladium hydride would provide a new insight on designing efficient and robust electrocatalysts for nitrogen fixation.     

A Janus Fe‐SnO2 Catalyst that Enables Bifunctional Electrochemical Nitrogen Fixation

Electrochemical N₂ reduction reactions (NRR) and the N₂ oxidation reaction (NOR), using H₂O and N₂, are a sustainable approach to N₂ fixation. To date, owing to the chemical inertness of nitrogen, emerging electrocatalysts for the electrochemical NRR and NOR at room temperature and atmospheric pressure remain largely underexplored. Herein, a new‐type Fe‐SnO₂ was designed as a Janus electrocatalyst for achieving highly efficient NRR and NOR catalysis. A high NH₃ yield of 82.7 μg h^?1 mg_cat.^?1 and a Faraday efficiency (FE) of 20.4 % were obtained for NRR. This catalyst can also serve as an excellent NOR electrocatalyst with a NO₃^? yields of 42.9 μg h^?1 mg_cat.^?1 and a FE of 0.84 %. By means of experiments and DFT calculations, it is revealed that the oxygen vacancy‐anchored single‐atom Fe can effectively adsorb and activate chemical inert N₂ molecules, lowering the energy barrier for the vital breakage of N≡N and resulting in the enhanced N₂ fixation performance.     

MoS2-Based Catalysts for N2 Electroreduction to NH3 – An Overview of MoS2 Optimization Strategies

The nitrogen reduction reaction (NRR) has become an ideal alternative to the Haber-Bosch process, as NRR possesses, among others, the advantage of operating under ambient conditions and saving energy consumption. The key to efficient NRR is to find a suitable electrocatalyst, which helps to break the strong N≡N bond and improves the reaction selectivity. Molybdenum disulfide (MoS₂) as an emerging layered two-dimensional material has attracted a mass of attention in various fields. In this minireview, we summarize the optimization strategies of MoS₂-based catalysts which have been developed to improve the weak NRR activity of primitive MoS₂. Some theoretical predictions have also been summarized, which can provide direction for optimizing NRR activity of future MoS₂-based materials. Finally, an outlook about the optimization of MoS₂-based catalysts used in electrochemical N₂ fixation are given.     

商用氧化铟锡玻璃:室温高效还原氮气的催化剂电极

NH₃作为一种必需的活化氮源,在化肥、染料、爆炸物和药物等的制造中起到了关键作用;同时,它也是一种在交通运输领域具有吸引力的无碳能源载体.工业上生产氨气使用典型的哈伯-博世工艺,但是此工艺涉及大量的能源消耗和碳排放,给环境带来巨大的压力.电化学氮还原反应(NRR)能够在温和环境下实现环境友好、节能的氨合成,但此过程需要高效的电催化剂.高效的NRR催化剂(Au、Ag、Pd和Ru)储量少、成本高,阻碍了它的实际应用.因此,设计和开发由地球上丰富的元素制成的具有成本效益的催化剂来代替NRR催化剂意义重大.本课题组最近的研究(Chem.Commun.,2018,54,12966-12969)表明,SnO2在环境条件下具有电催化氧化活性,但其低电导率限制了其性能,可通过氟掺杂或石墨烯杂化予以解决.氧化铟锡(ITO)作为一种含SnO2的材料,导电性好,可望用于NRR的高效电催化剂中.因此,本文采用商用氧化铟锡玻璃(ITO/G)作为催化剂电极,在温和环境条件下进行N₂-NH₃的电化学转化,并呈现出对生成氨气有较高的选择性.XRD和XPS结果表示,商用ITO/G中存在In,Sn和O元素;SEM显示ITO/G具有清晰的纳米薄膜结构和267 nm的截面厚度;相应的EDX谱图显示In,Sn和O元素分布均匀,且原子比为32.11:3.16:64.74.采用紫外-可见光谱及线性扫描伏安和恒电位极化等电化学测试研究了商用ITO/G的NRR活性.在0.5 M LiClO4电解液中测试时,于-0.40 V vs.RHE条件下,ITO/G的NH₃产率为1.06×10^-10 mol s^-1 cm^-2,其法拉第效率为6.17%.15N同位素标记实验证实了所测到的NH₃是由ITO/G催化的N₂电还原反应生成的.利用第一性原理计算探讨了在ITO催化剂上可能的NRR反应机理,确定了ITO催化剂的NRR活性位点、N₂化学吸附活性位点以及NRR的反应途径.此外,24 h恒电位(-0.40 V vs.RHE)极化测试和2 h恒电位极化(-0.40 V vs.RHE)测试后的XRD和SEM结果表明,该催化剂具有较高的电化学稳定性.综上所述,商用ITO/G用作在环境条件下将N₂转化为NH₃的有效催化剂电极,将为开发人工固定氮气的ITO基纳米结构提供一种研究途径.     

Amorphous core/shell Ti-doped SnO2 with synergistically improved N2 adsorption/activation and electrical conductivity for electrochemical N2 reduction

Electrochemical nitrogen reduction reaction (NRR) has been considered as an appealing and sustainable method to produce ammonia from N₂ under ambient conditions, attracting increasing interest. Limited by low solubility of N₂ in water and high stability of NN triple bond, developing NRR electrocatalysts with both strong N₂ adsorption/activation and high electrical conductivity remain challenging. Here, we demonstrate an efficient strategy to develop NRR electrocatalyst with synergistically enhanced N₂ adsorption/activation and electrical conductivity by heteroatom doping. Combining computational and experimental study, the DFT-designed Ti-doped SnO₂ exhibits significantly enhanced NRR performance with ammonia yield rate of 13.09 µg h^?1 mg^?1 at ?0.2 V vs. RHE. Particularly, the Faradaic efficiency reaches up to 42.6%, outperforming most of Sn-based electrocatalysts. The fundamental mechanism for improving NRR performance of SnO₂ by Ti doping is also revealed. Our work highlights a powerful strategy for developing high-activity electrocatalysts for NRR and beyond.     

First-principles study on Fe2B2 as efficient catalyst for nitrogen reduction reaction

Ammonia (NH₃) is considered an attractive candidate as a clean, highly efficient energy carrier. The electrocatalytic nitrogen reduction reaction (NRR) can reduce energy input and carbon footprint; therefore, rational design of effective electrocatalysts is essential for achieving high-efficiency electrocatalytic NH₃ synthesis. Herein, we report that the enzymatic mechanism is the more favourable pathway for NRR, due to lower limiting potential (−0.44 V), lower free energy (only 0.02 eV) of the first hydrogenation step (*N–N to *NH–N), and more electron transfer from Fe₂B₂ to the reaction species. In addition, both vacancies and dopants can be helpful in reducing the reaction energy barrier of the potential-determining step. Therefore, we have demonstrated that Fe₂B₂ is a potential new candidate for effective NRR and highlighted its potential for applications in electrocatalytic NH₃ synthesis.