Chem
·
2023
·
IF 23.5
Yibo Wang,Rongpeng Ma,Zhaoping Shi,Hongxiang Wu,Shuai Hou,Ying Wang,Changpeng Liu,Junjie Ge,Wei Xing
The acidic oxygen evolution reaction (OER) faces great difficulty in concurrently addressing the site-specific activity and stability of the up-to-date choice Ir-based catalysts. Herein, we adopted a new inverse doping strategy to devise a Ti atomic doping into the surficial IrO x /Ir matrix to investigate the boosting effect of Ir-O-Ti motifs toward OER. Notably, only 1.92 wt % Ti introduction leads to 3.6 times and an order of magnitude improvement in intrinsic activity and stability, respectively, ascribed to the creation of abundant Ir-O-Ti motifs. While the Ti sites donate electrons to weaken the Ir-O interaction and thereby ignite Ir sites activity via adsorbate evolution mechanism (AEM), the restricted O–O bond formation in the lattice oxygen mechanism (LOM) and the widened stable region of Ir species help enhance the stability. This work provides a novel insight into the reactivity of atomic-level interface motifs in heterogeneous components, which inspires further design of advanced catalysts.
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ANALYTICA CHIMICA ACTA
·
2022
·
IF 6.911
Yunwen Shen,Zhentao Sun,Pei Hu,Wei-Jun Cai,Yiwen Pan
High concentrations of redox substances in the solution may cause severe electrode potential drift, resulting in the inaccuracy of in situ measurements . Sulfide anion , a highly reductive substance, is the killer of all metal oxide electrodes because of its small size and strong surface activity. We first proposed to use SPEEK (SP) with silica-stabilized imidazole-type ionic liquid (ImIL) to fabricate a composite film (SP/SiO x /ImIL) to achieve a high anti-interference ability for metal electrodes. The composite film was especially designed to address the interference caused by sulfide anions and other small-sized anions ( i.e., I − , F − and ascorbic acid). The reduced proton conductivity was restored by introducing ImIL into SPEEK matrix. Open circuit potential tests showed that the potential of the SP/SiO x /ImIL modified IrO x electrode fluctuated within 0.3 mV in 30 min continuous test at a concentration of 10 −3 M Na 2 S, exhibiting good stability in moderately high sulfide solution. It also exhibited fast response and good reversibility. In addition, no potential drift was measured under other anions interferences. XPS survey verified that the Ir 4+ /Ir 3+ ratio of the IrO x electrode did not change before and after application in sulfide-containing solution, indicating that the SP/SiO x /ImIL composite film has good anion isolation capacity.
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高影响因子
ACS Catalysis
·
2020
·
IF 12.35
Peikun Zhang,Wei Wang,Hui Wang,Yanbo Li,Chunhua Cui
Although much is known about the increased rate of a catalyst required for the oxygen evolution reaction (OER), the hole accumulation behaviors of the catalyst on both photo- and dark electrodes remain uncovered. We present a rational tuning of the hole-accumulation and hole-transfer ability of a catalyst by in situ deposition of IrOx on NiOx islands on model Si electrodes and we demonstrate a distinct hole accumulation behavior during the OER through electrochemical methods, in situ UV–vis and Raman spectroelectrochemistry. We find that the NiOx islands with <10% coverage on an n++-Si dark electrode demonstrate a 6-fold higher capacity of hole accumulation relative to that on an n-Si photoanode under illumination. A further in situ targeted deposition of soluble hexahydroxyiridate on the NiOx leads to the formation of NiOx/IrOx junctions, where the IrOx further depletes the extracted holes by NiOx from the n-Si photoanode decreasing the overpotential by ∼260 mV at 20 mA cm–2, yet the IrOx promotes the hole accumulation at the NiOx/IrOx on the dark electrodes presenting a similar decrease of the overpotential. In contrast to the dark-holes, an extremely lower charging level of photogenerated holes of the same catalyst at the identical current density reasoned a seemingly higher reactivity to drive the OER, and reasonably demonstrated a stronger oxidation/corrosion to the Si electrode.
研究领域:
电化学
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材料科学
·
催化
·
可再生能源
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ELECTROCHIMICA ACTA
·
2024
·
IF 5.5
Xingxing Duan,Huiyuan Liu,Weiqi Zhang,Qiang Ma,Qian Xu,Lindiwe Khotseng,Huaneng Su
The stability of supported Ir-based catalysts in acid oxygen evolution reaction (OER) remains a pressing challenge, which hinders the commercial viability of proton exchange membrane water electrolysis (PEMWE) technology. Herein, we propose a cerium doping strategy to enhance the stability of supported Ir-based catalyst toward OER. The Ce-doped supported catalysts, designated as Ce-IrO x /TiN, were synthesized using an organic colloidal method. Transmission Electron Microscopy (TEM) analysis reveals highly dispersed IrO x nanoparticles averaging 1.5 nm on the TiN support. X-ray Photoelectron Spectroscopy (XPS) investigations further elucidate that Ce doping effectively stabilizes the Ir species predominantly in states below 4 + , crucial for modulating the surface electronic structure and thereby improving both the activity and stability of the catalysts. Electrochemical characterization highlights the superior performance of the optimized catalyst, 6 %-Ce-IrO x /TiN, with an impressively low overpotential of 242 mV at 10 mA cm −2 and a Tafel slope of 57.5 mV dec −1 , showcasing its significance in facilitating OER. Moreover, its mass activity surpasses that of commercial IrO 2 by 5.1 times at 1.7 V. Prolonged constant current testing further demonstrates the exceptional stability of the catalyst, affirming the critical role of Ce doping as a pivotal strategy for enhancing the stability of supported Ir-based catalysts and advancing the prospects for robust OER performance in PEMWE systems.
研究领域:
材料科学
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电化学
·
能源技术
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高影响因子
JOURNAL OF CATALYSIS
·
2019
·
IF 7.723
Xiaoyue Wan,Qi Zhang,Mingming Zhu,Yi Zhao,Yongmei Liu,Chunmei Zhou,Yanhui Yang,Yong Cao
Site-selective deoxygenation of hydroxyl groups represents essential processes to access valuable functionalized bio-based compounds with industrial potential. One of the challenging tasks in this context is to convert biodiesel-derived glycerol in the presence of abundant water directly to 1,3-propanediol (1,3-PDO), a key component of the emerging polymer industry. Herein, a monometallic iridium supported on H-ZSM-5 in the absence of Re oxophilic metal oxides was prepared via grinding-assisted impregnation procedures and attempted as an effective and recyclable catalyst for the aqueous-phase selective hydrogenolysis of glycerol toward 1,3-PDO in the absence of acid additives. The results revealed the necessity to control the Ir domain dispersions, Ir 0 /Ir 3+ ratio and the amounts of overall acid/Brönsted acid sites. Activity depended linearly on the amount of overall and Brönsted acid sites, and 1,3-PDO selectivity increased in the presence of Ir-induced Brönsted acid sites, denoted as Ir-O(H)-H-ZSM-5. We speculate that Ir-O(H)-H-ZSM-5 are generated by the interfacial synergistic interaction between IrO x and H-ZSM-5 through hydrogen spillover and reverse hydrogen spillover according to the reported literatures. The reaction mechanism to elucidate the role of Ir-O(H)-H-ZSM-5 sites in glycerol hydrogenolysis was also postulated based on extensive characterization and catalytic reaction results.
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高影响因子
IEEE SENSORS JOURNAL
·
2023
·Vol. 23
·期 4
·3475-3484
·
IF 4.3
Jiawen Yin,Wei Chen,Wanlei Gao,Xin Zhang,Bo Tang,Qinghui Jin
Considering the indispensable of pH for tap water, a pH sensor with the characteristics of an implantable, long-term stable, and long lifetime is urgently needed for on-line and in situ pH monitoring in tap water, but this is always a challenging issue. In this article, a competitive integrated electrochemical pH sensor is developed and batch manufactured via micro-electro-mechanical system (MEMS). A dense and ultrasensitive IrOx electrode is obtained for almost 1.5 times Nernst response (−82.88 mV/pH), after preparation process optimization. A Si-Si3N4-KCl agar gel-polydimethylsiloxane (PDMS) multilayer structured Ag/AgCl electrode is designed and proven to be a long lifetime (>40 days) and be stable. By integrating with the IrOx film and solid-state Ag/AgCl electrode on a mini chip and verifying the effectiveness of the as-fabricated sensor by pH detection, the miniature pH sensor demonstrates wide detection range (1.8–12), stirring sensitivity, desirable linearity ( ${R}^{2}=0.999$ ), ideal repeatability and good resistance to other interference substances. Particularly, by employing the mass-production technique, favorable response consistency (relative standard deviation (RSD) < 2%) is witnessed, offering the opportunity to mass-produce the proposed sensor in the future. What’s more, the sensor still kept 91.7% sensitivity when compared to the sensitivity obtained at its initial state, after continuously operating for 32 days. Undoubtedly, the sensitive, durable, miniaturized, and mass-produced pH sensor proposed in this article is a competitive device to implant into the water pipeline for pH in situ online monitoring.
研究领域:
生物医学工程
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微纳传感技术
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环境监测
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电化学传感器
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转化医学
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水质分析
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植入式器件
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Mingzhi Zhang,Shujuan Wang,Hongwei Guo,Fan Lv,Tianjiao Ling,Yi Cao,Hongwei Li,Huihua Wang,Jinxin Chen,Ruiqi Guo
Self-supported electrodes featuring transition metals encapsulated within carbon nanotubes (CNTs) are promising bifunctional catalytic electrodes for overall water splitting due to their binder-free fabrication (eliminating costly Nafion), high electrical conductivity, mechanical strength, and low cost. However, challenges remain, including insufficient catalytic activity and stability, as well as underutilization of the CNTs’ functionality. Herein, we strategically modified a Fe-based self-supported electrode with ultrafine IrOx nanoclusters (IrOx NCs), creating Fe@CNTs/IrOx NCs/CC, which exhibits enhanced bifunctional performance for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1.0 M KOH. The optimized Fe10@CNTs/IrOx NCs/CC requires low HER and OER overpotentials of 36.7 mV and 203.5 mV at the current density of ± 10 mA cm–2. It also shows a high mass activity of 214.8 A gIr–1 at 100 mV. Moreover, water splitting cells employing Fe10@CNTs/IrOx NCs/CC as both the anode and cathode require only 1.50 V to reach 10 mA cm–2 and demonstrate stable operation exceeding 100 h. Detailed theoretical calculations prove that the IrOx NCs synergistically enhance HER kinetics by promoting both the H2O adsorption-dissociation efficiency and optimized *H desorption. For the OER process, they significantly lower the energy barrier of the rate-determining step (*O → *OOH), thereby accelerating the overall water splitting process of Fe10@CNTs/IrOx NCs/CC. This work highlights an innovative research route for boosting the water splitting performance through targeted modification of the self-supported electrode.
研究领域:
电催化
·
能源材料
·
纳米材料
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水分解
·
可再生能源
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 47
·期 5
·2619-2625
·
IF 3.925
Xuefeng Wang,Haeseong Jang,Zijian Li,Haisen Li,Guangkai Li,Min Gyu Kim,Xuqiang Ji,Qing Qin,Xien Liu
Promoting the activity of Ir-based nanomaterials for oxygen evolution reaction (OER) in acid media without losing their durability is crucial for reducing overpotentials in energy conversion, such as electrochemical water splitting. Here, a nanocomposite composed of a-IrOx and lanthanum salt (LaCO3OH) was constructed to further improve its OER activity by tuning the electronic structure of a-IrOx, because a-IrOx is a well-known critical material as the active layer of Ir-based anodic catalysts. The interaction between Ir and La via O atoms as a bridge in the catalyst IrOx/LaCO3OH, verified by X-ray absorption near edge structure spectroscopy, tunes the electronic structure of a-IrOx and thus obviously enhances its activity for the OER in acid media, compared with commercially available IrO2 as well as most of the reported Ir-based OER electrocatalysts. The overpotential of IrOx/LaCO3OH at a current density of 10 mA cm−2 is 255 mV with a Tafel slope of 55 mV dec−1. This work reveals that the strong electronic interaction between Ir- and La-based materials can efficiently improve activity and reduce energy consumption, as well as enlarging the family of acidic OER electrocatalysts.
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ACS Applied Energy Materials
·
2022
·
IF 6.959
Jianhua Liao,Yameng Wang,Ming Chen,Min Wang,Jiantao Fan,Hui Li,Haijiang Wang,Lin Zeng,Tianshou Zhao
The addition of an oxygen evolution electrocatalyst to an anode catalyst layer is demonstrated as a practical approach to address the voltage reversal of proton exchange membrane fuel cells (PEMFCs). In this work, IrOX nanoparticles uniformly deposited on niobium-doped TiO2 (IrOX/Nb0.1Ti0.9O2) by a sol–gel method are employed as reversal tolerant anodes (RTAs) for PEMFCs. The membrane electrode assembly (MEA) with this RTA possesses a reversal tolerance time of 29.1 min, which is the best result among all the as-prepared MEAs. Meanwhile, the decrease in the cell voltage of this MEA after reversal testing is only 61 mV at a current density of 1.2 A cm–2 with a degradation rate of 11.1%. The improved reversal tolerance is attributed, in part, to the uniformly distributed IrOX nanoparticles, boosting the oxygen evolution reaction and, in part, to avoid the carbon oxidation reaction by the application of a noncarbon support. This result can lay a fundamental basis for the application of RTA based on a noncarbon support to improve the anode reversal tolerance for PEMFCs.
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ACS Catalysis
·
2025
·
IF 13.1
Qiuyan Chu,Yanpu Niu,Haolan Tao,Honglai Liu,Quan Li,Cheng Lian,Jingkun Li
Iridium-based electrocatalysts are the most promising candidates for the acidic oxygen evolution reaction (OER). Considering their high cost and scarcity, it is imperative to maximize atom utilization and enhance the intrinsic activity of iridium. In this work, IrOx sub-2 nm clusters are stabilized on TiO2 supports via metal support interaction (MSI) induced by vacancy defects in TiO2. The strength of MSI is readily tuned by the type of vacancies: oxygen vacancies in TiO2 (VO-TiO2) induce the adsorbed MSI with relatively weak strength, while titanium vacancies in TiO2 (VTi-TiO2) lead to the strong embedded MSI. The tunable MSI further modulates the electronic structure of IrOx sub-2 nm clusters. IrOx/VO-TiO2 with adsorbed MSI exhibits an optimized electronic structure with a downshifted d-band center of IrOx, resulting in a reduced binding energy with oxygen and a low energy barrier of the rate-determining step for OER. Consequently, IrOx/VO-TiO2 delivers an activity twice that of commercial IrO2 and a good stability for 120 h in a practical proton exchange membrane water electrolyzer. Our study provides a guideline for the rational design of acidic OER catalysts based on modulating the electronic structure of IrOx sub-2 nm clusters via tunable MSI.
研究领域:
材料科学
·
电化学
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Weiwei Han,Xinuo Cai,Jiahong Liao,Yi He,Chunlin Yu,Xingwang Zhang
The development of proton exchange membrane water electrolysis is a promising technology for hydrogen production, which has always been restricted by the slow kinetics of the oxygen evolution reaction (OER). Although IrOx is one of the benchmark acidic OER electrocatalysts, there are still challenges in designing highly active and stable Ir-based electrocatalysts for commercial application. Herein, a Ru-doped IrOx electrocatalyst with abundant twin boundaries (TB-Ru0.3Ir0.7Ox@ITO) is reported, employing indium tin oxide with high conductivity as the support material. Combing the TB-Ru0.3Ir0.7Ox nanoparticles with ITO support could expose more active sites and accelerate the electron transfer. The TB-Ru0.3Ir0.7Ox@ITO exhibits a low overpotential of 203 mV to achieve 10 mA cm–2 and a high mass activity of 854.45 A g–1noble metal at 1.53 V vs RHE toward acidic OER, which exceeds most reported Ir-based OER catalysts. Moreover, improved long-term stability could be obtained, maintaining the reaction for over 110 h at 10 mA cm–2 with negligible deactivation. DFT calculations further reveal the activity enhancement mechanism, demonstrating the synergistic effects of Ru doping and strains on the optimization of the d-band center (εd) position and the adsorption free energy of oxygen intermediates. This work provides ideas to realize the trade-off between high catalytic activity and good stability for acidic OER electrocatalysts.
研究领域:
材料科学
·
电化学
·
催化科学
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高影响因子
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