Tuning electronic structure of PdZn nanocatalyst via acid-etching strategy for highly selective and stable electrolytic nitrogen fixation under ambient conditions

Abstract(#br)Although ambient nitrogen fixation powered by renewable electricity is emerging as a highly attractive alternative to the classical Haber–Bosch process, it still remains extremely challenging. In this work, a facile acid-etching strategy was employed to synthesize defect-rich PdZn nanoparticles (NPs) supported on N-doped hollow carbon polyhedrons (etched-PdZn/NHCP), which could serve as an attractive and efficient electrocatalyst for the nitrogen reduction reaction (NRR). The synthesized etched-PdZn/NHCP electrocatalyst achieved higher NH 3 yields (5.28 μg mg -1 cat. h -1 ) than pristine PdZn NPs in a phosphate buffer solution. Remarkably, the existence of abundant defects in the etched PdZn NPs favored N 2 adsorption and activation, resulting in significantly high Faradaic efficiency (FE) of 16.9% towards NH 3 and outperforming previously reported Pd-based NRR electrocatalysts. Furthermore, the etched-PdZn/NHCP cathode exhibited good long-term electrochemical durability with both the NH 3 production and the FE remaining practically stable after 50 h of electrolysis

N-doped carbon shell encapsulated PtZn intermetallic nanoparticles as highly efficient catalysts for fuel cells

Abstract(#br)The high cost and poor durability of Pt nanoparticles (NPs) have always been great challenges to the commercialization of proton exchange membrane fuel cells (PEMFCs). Pt-based intermetallic NPs with a highly ordered structure are considered as promising catalysts for PEMFCs due to their high catalytic activity and stability. Here, we reported a facile method to synthesize N-doped carbon encapsulated PtZn intermetallic (PtZn@NC) NPs via the pyrolysis of Pt@Zn-based zeolitic imidazolate framework-8 (Pt@ZIF-8) composites. The catalyst obtained at 800 °C (10%-PtZn@NC-800) was found to exhibit a half-wave potential ( E 1/2 ) up to 0.912 V versus reversible hydrogen electrode (RHE) for the cathodic oxygen reduction reaction in an acidic medium, which shifted by 26 mV positively..

Platinum-nickel alloy excavated nano-multipods with hexagonal close-packed structure and superior activity towards hydrogen evolution reaction

铂镍合金在氢析出(HER)、氧还原(ORR)等重要能量转化反应中具有优异催化性质，受到了人们广泛的关注。近日，谢兆雄教授课题组通过简单的溶剂热方法，首次合成出六方晶系的铂镍合金枝状纳米晶，其中每个枝杈结构由六个{11-20}高能晶面裸露的超薄纳米片组装而成。与面心立方晶系铂镍合金相比，亚稳态的六方晶系铂镍合金在HER反应中表现出更加优异的性质。当电流密度为10 mA·cm-2时，其过电位仅有65 mV，同时质量电流密度高达3.03 mA·µgPt-1 (-70 m V vs. RHE)，是目前为止报道的HER催化剂中质量活性最高的，其突出的催化性能主要来源于晶相作用(同质异晶)及大的比表面积。该项工作为发展高催化性能的铂基合金纳米晶提供了新的研究思路。该研究是在谢兆雄教授和蒋亚琪副教授指导下，与傅钢教授共同合作完成。实验部分由博士生曹振明（第一作者）、陈巧丽、沈守宇、卢邦安，硕士生李慧齐以及博士后张嘉伟共同完成，理论计算部分由傅钢教授课题组完成。【Abstract】Crystal phase regulations may endow materials with enhanced or new functionalities. However, syntheses of noble metal-based allomorphic nanomaterials are extremely difficult, and only a few successful examples have been found. Herein, we report the discovery of hexagonal close-packed Pt–Ni alloy, despite the fact that Pt–Ni alloys are typically crystallized in face-centred cubic structures. The hexagonal close-packed Pt–Ni alloy nano-multipods are synthesized via a facile one-pot solvothermal route, where the branches of nano-multipods take the shape of excavated hexagonal prisms assembled by six nanosheets of 2.5nm thickness. The hexagonal close-packed Pt–Ni excavated nano-multipods exhibit superior catalytic property towards the hydrogen evolution reaction in alkaline electrolyte. The overpotential is only 65mV versus reversible hydrogen electrode at a current density of 10 mAcm-2 , and the mass current density reaches 3.03mA µgPt-1 at -70mV versus reversible hydrogen electrode, which outperforms currently reported catalysts to the best of our knowledge.This work was supported by the National Basic Research Program of China (Grant 2015CB932301), the National Natural Science Foundation of China (Grants 21333008, 21603178 and J1030415) and the Natural Science Foundation of Fujian Province of China (No. 2014J01058). 该研究工作得到科技部（批准号：2015CB932301）、国家自然科学基金委（批准号：21333008, 21603178 和 J1030415）和福建省自然科学基金委（No. 2014J01058）的大力资助与支持

Seizing the window of opportunity to mitigate the impact of climate change on the health of Chinese residents

The health threats posed by climate change in China are increasing rapidly. Each province faces different health risks. Without a timely and adequate response, climate change will impact lives and livelihoods at an accelerated rate and even prevent the achievement of the Healthy and Beautiful China initiatives. The 2021 China Report of the Lancet Countdown on Health and Climate Change is the first annual update of China’s Report of the Lancet Countdown. It comprehensively assesses the impact of climate change on the health of Chinese households and the measures China has taken. Invited by the Lancet committee, Tsinghua University led the writing of the report and cooperated with 25 relevant institutions in and outside of China. The report includes 25 indicators within five major areas (climate change impacts, exposures, and vulnerability; adaptation, planning, and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement) and a policy brief. This 2021 China policy brief contains the most urgent and relevant indicators focusing on provincial data: The increasing health risks of climate change in China; mixed progress in responding to climate change. In 2020, the heatwave exposures per person in China increased by 4.51 d compared with the 1986–2005 average, resulting in an estimated 92% increase in heatwave-related deaths. The resulting economic cost of the estimated 14500 heatwave-related deaths in 2020 is US$176 million. Increased temperatures also caused a potential 31.5 billion h in lost work time in 2020, which is equivalent to 1.3% of the work hours of the total national workforce, with resulting economic losses estimated at 1.4% of China’s annual gross domestic product. For adaptation efforts, there has been steady progress in local adaptation planning and assessment in 2020, urban green space growth in 2020, and health emergency management in 2019. 12 of 30 provinces reported that they have completed, or were developing, provincial health adaptation plans. Urban green space, which is an important heat adaptation measure, has increased in 18 of 31 provinces in the past decade, and the capacity of China’s health emergency management increased in almost all provinces from 2018 to 2019. As a result of China’s persistent efforts to clean its energy structure and control air pollution, the premature deaths due to exposure to ambient particulate matter of 2.5 μm or less (PM2.5) and the resulting costs continue to decline. However, 98% of China’s cities still have annual average PM2.5 concentrations that are more than the WHO guideline standard of 10 μg/m3. It provides policymakers and the public with up-to-date information on China’s response to climate change and improvements in health outcomes and makes the following policy recommendations. (1) Promote systematic thinking in the related departments and strengthen multi-departmental cooperation. Sectors related to climate and development in China should incorporate health perspectives into their policymaking and actions, demonstrating WHO’s and President Xi Jinping’s so-called health-in-all-policies principle. (2) Include clear goals and timelines for climate-related health impact assessments and health adaptation plans at both the national and the regional levels in the National Climate Change Adaptation Strategy for 2035. (3) Strengthen China’s climate mitigation actions and ensure that health is included in China’s pathway to carbon neutrality. By promoting investments in zero-carbon technologies and reducing fossil fuel subsidies, the current rebounding trend in carbon emissions will be reversed and lead to a healthy, low-carbon future. (4) Increase awareness of the linkages between climate change and health at all levels. Health professionals, the academic community, and traditional and new media should raise the awareness of the public and policymakers on the important linkages between climate change and health.</p