非贵金属活化预处理化学镀Ni包覆TiC陶瓷粉体的研究

采用非贵金属活化预处理对TiC陶瓷粉体进行化学镀前处理,预处理后通过常温超声波辅助化学镀方法成功制备了Ni包覆TiC陶瓷粉体,通过场发射扫描电子显微镜(FE-SEM)和能谱(EDS)研究分析了原始TiC粉体、非贵金属活化预处理后TiC粉体和Ni包覆TiC粉体表面形貌,探讨了化学镀Ni包覆TiC陶瓷粉体的生长机理。结果表明:非贵金属活化预处理后TiC陶瓷粉体表面出现了大量的缺陷(台阶),化学镀Ni包覆TiC陶瓷粉体表面Ni层覆盖完整、致密均匀;Ni颗粒的形核、长大和聚集的过程为:化学镀溶液中的反应物在TiC表面缺陷上吸附,发生氧化-还原反应沉积出Ni颗粒;Ni颗粒依附"线条状"突起以"线型"方式长大、弯曲、分叉和聚集,而后缠绕成"胞状"结构,犹如"缠毛线团"。"胞状"结构Ni颗粒不断长大聚集,最后成膜。

非贵金属活化氧化铝陶瓷基板化学镀铜研究

提出一种新型的非贵金属活化法辅助二次化学镀的氧化铝陶瓷基板化学镀铜工艺,成功制备了表面完整、分布均匀的铜镀层,进一步通过冷场发射扫描电镜（FE-SEM）做了具体分析。可以发现,经预处理活化之后的氧化铝基板表面产生一定程度的表面缺陷,主要包括不同梯度的台阶,颗粒与颗粒之间的边缘化以及‘地道式’的孔洞。在第一次化学镀铜沉积一定量的铜颗粒之后表面仍存在大量的空隙,即未镀区域。但在二次化学镀工艺之后,表面完全覆盖镀层,其中镀层表面上小的圆球状（2~3μm）铜颗粒夹杂在大的胞状（4~5μm）颗粒之间,整体上为颗粒与颗粒的物理聚集然后通过堆垛而形成的。

塑料化学镀前活化处理的研究现状

活化处理是塑料表面金属化成功与否的关键,继而影响到后续化学镀的质量。从贵金属活化、现代技术辅助贵金属活化和非贵金属活化3个方面对塑料表面活化处理的研究现状进行了综述。着重对现代技术辅助贵金属活化工艺,如微波辐照、激光辐照等技术,非贵金属活化工艺如嫁接有机介质中间层、接枝共聚改性、等离子辐照等工艺进行了总结;介绍了新型活化处理工艺的一般过程和活化效果,指出了化学镀前活化处理未来的研究方向。

Progress in research on catalysts for catalytic oxidation of formaldehyde

Formaldehyde（HCHO）is carcinogenic and teratogenic,and is therefore a serious danger to human health.It also adversely affects air quality.Catalytic oxidation is an efficient technique for removing HCHO.The development of highly efficient and stable catalysts that can completely convert HCHO at low temperatures,even room temperature,is important.Supported Pt and Pd catalysts can completely convert HCHO at room temperature,but their industrial applications are limited because they are expensive.The catalytic activities in HCHO oxidation of transition-metal oxide catalysts such as manganese and cobalt oxides with unusual morphologies are better than those of traditional MnO2,Co3O4,or other metal oxides.This is attributed to their specific structures,high specific surface areas,and other factors such as active phase,reducibility,and amount of surface active oxygens.Such catalysts with various morphologies have great potential and can also be used as catalyst supports.The loading of relatively cheap Ag or Au on transition-metal oxides with special morphologies potentially improves the catalytic activity in HCHO removal at room temperature.The preparation and development of new nanocatalysts with various morphologies and structures is important for HCHO removal.In this paper,research progress on precious-metal and transition-metal oxide catalyst systems for HCHO oxidation is reviewed; topics such as oxidation properties,structure–activity relationships,and factors influencing the catalytic activity and reaction mechanism are discussed.Future prospects and directions for the development of such catalysts are also covered.

Acid promoted Ni/NiO monolithic electrode for overall water splitting in alkaline medium

Exploring and designing bi-functional catalysts with earth-abundant elements that can work well for both hydrogen evolution reaction（HER） and oxygen evolution reaction（OER） in alkaline medium are of significance for producing clean fuel to relieve energy and environment crisis.Here,a novel Ni/NiO monolithic electrode was developed by a facile and cost-effective acid promoted activation of Ni foam.After the treatment,this obtained monolithic electrode with a layer of NiO on its surface demonstrates rough and sheet-like morphology,which not only possesses larger accessible surface area but also provides more reactive active sites. Compared with powder catalysts,this monolithic electrode can achieve intimate contact between the electrocatalyst and the current collector,which will alleviate the problem of pulverization and enable the stable function of the electrode. It can be served as an efficient bi-functional electrocatalyst with an overpotential of 160 mV for HER and 290 mV for OER to produce current densities of 10 mA cm^（-2） in the alkaline medium. And it maintains benign stability after 5,000 cycles,which rivals many recent reported noble-metal free catalysts in 1.0mol L^（-1） KOH solution. Attributed to the easy,scalable methodology and high catalytic efficiency,this work not only offers a promising monolithic catalyst but also inspires us to exploit other inexpensive,highly efficient and self-standing noble metalfree electrocatalysts for scale-up electrochemical water-splitting technology.

Melamine-assisted synthesis of ultrafine Mo_(2)C/Mo_(2)N@N-doped carbon nanofibers for enhanced alkaline hydrogen evolution reaction activity

Noble metal-free electrocatalysts with high activity are highly desirable for the large-scale application of hydrogen evolution reaction(HER). Mo_(2) C-based nanomaterials have been proved as a promising alternative to noble metal-based electrocatalysts owing to the Pt-resembled d-band density and optimal intermediates-adsorption properties.However, the aggregation and excessive growth of crystals often occur during their high-temperature synthesis procedure, leading to low catalytic utilization. In this study, the ultrafine Mo_(2) C/Mo_(2) N heterostructure with large surface and interface confined in the N-doped carbon nanofibers(NCNFs) was obtained by a melamine-assisted method. The synergistic effect of Mo_(2) C/Mo_(2) N heterostructure and plenty active sites exposed on the surface of ultrafine nanocrystals improves the electrocatalytic activity. Meanwhile, the N-CNFs ensure fast charge transfer and high structural stability during reactions. Moreover, the in-situ synthesis method strengthens the interfacial coupling interactions between Mo_(2)C/Mo_(2) N heterostructure and N-CNFs, further enhancing the electronic conductivity and electrocatalytic activity. Owing to these advantages, Mo_(2)C/Mo_(2) N@N-CNFs exhibit excellent HER performance with a low overpotential of 75 mV at a current density of 10 mV cm^(-2) in alkaline solution, superior to the single-phased Mo_(2)C counterpart and recently reported Mo_(2)C/Mo_(2) N-based catalysts. This study highlights a new effective strategy to design efficient electrocatalysts via integrating heterostructure, nanostructure and carbon modification.

A highly-efficient oxygen evolution electrode based on defective nickel-iron layered double hydroxide

Exploring efficient and cost-effective electro- catalysts for oxygen evolution reaction （OER） is critical to water splitting. While nickel-iron layered double hydroxide （NiFe LDH） has been long recognized as a promising non- precious electrocatalyst for OER, its intrinsic activity needs further improvement. Herein, we design a highly-efficient oxygen evolution electrode based on defective NiFe LDH na- noarray. By combing the merits of the modulated electronic structure, more exposed active sites, and the conductive elec- trode, the defective NiFe LDH electrocatalysts show a low onset potential of 1.40 V （vs. RHE）. An overpotential of only 200 mV is required for 10 mA cm-2, which is 48 mV lower than that of pristine NiFe-LDH. Density functional theory plus U （DFT＋U） calculations are further employed for the origin of this OER activity enhancement. We find the introduction of oxygen vacancies leads to a lower valance state of Fe and the narrowed bandgap, which means the electrons tend to be ea- sily excited into the conduction band, resulting in the lowered reaction overpotential and enhanced OER performance.

Carbon-CeO interface confinement enhances the chemical stability of Pt nanocatalyst for catalytic oxidation reactions

Noble metals are downsized to nano-/subnanoscale to improve their catalytic activity and atom-economy.However,the stabilities in chemical state and catalytic performance of these nanocatalysts often suffer during harsh conditions.For Pt nanoparticles(NPs)supported on CeO2,activated oxygen diffused from the support over-stabilizes the active sites of Pt,degrading its performance at mild temperature.In this work,Pt nanocatalysts with unique structure of triple-junction are synthesized by selectively growing Pt NPs on the carbon-CeO2 interface.Impressively,the Pt NPs exhibit much enhanced catalytic stability and high activity for CO oxidation at mild temperature.The enhancement is attributed to electron donation from graphitized carbon and the confinement effect from the high-density nanopores of the CeO2 support.The triple-junction of Pt-C-CeO2,combining the merits of CeO2 for activating O2 and electron donating capability of carbon,provides new inspiration to the fabrication of high-performance nanocatalysts.