利用碳纳米纤维/Pt纳米片构建柔性电极用于葡萄糖检测

糖尿病是一种以高血糖为特征的代谢性疾病,严重威胁人类健康。血糖指标的监测在糖尿病的预防、诊断及治疗中发挥着重要作用。以聚丙烯腈为碳源,通过静电纺丝与热处理工艺制备了柔性碳纳米纤维膜,并利用恒电位电沉积法在自支撑碳纳米纤维膜上负载Pt纳米片构建柔性无酶葡萄糖传感器。结果表明,碳纳米纤维表面光滑,Pt纳米片逐渐生长并填满纳米纤维间隙,单个纳米片长100~200 nm,宽约100 nm。构建的柔性无酶葡萄糖传感器对葡萄糖的线性检测范围为7.5~87.5 mmol/L,灵敏度为6.41μA·(mmol/L)^(-1)·cm^(-2),最低检测限为14.04μmol/L,同时传感器表现出良好的抗干扰性、重复性和稳定性。该柔性电极材料制备方法简单,结合柔性电极和无酶传感器的优势,避免传统酶传感器重复性、稳定性及抗干扰性能差的问题,为柔性葡萄糖传感器的构建提供了可能。

Electrocatalytic ammonia synthesis catalyzed by mesoporous nickel oxide nanosheets loaded with Pt nanoparticles

Owing to its cost‐effectiveness and adjustable eight‐electron distribution in the 3d orbital,nickel oxide(NiO)is considered an effective electrocatalyst for an ambient electrochemical nitrogen reduction reaction(NRR).However,because of the low conductivity of the transition metal oxide electrocatalyst,its application in this field is limited.In this study,we found that the doping of NiO nanosheets with a small amount(3–10 nm)of Pt nanoparticles(Pt/NiO‐NSs)leads to considerable improvements in the Faradaic efficiency(FE)and NH_(3) yield compared with those obtained using pure NiO,breaking the common perception that commercial Pt‐based electrocatalysts demonstrate little potential for NRR due to their high hydrogen evolution tendency.In a 0.1 mol/L Na_(2)SO_(4) solution at−0.2 V vs.RHE,a typical Pt/NiO‐2 sample exhibits an optimum electrochemical NH_(3) yield of 20.59μg h^(–1)mg^(–1)cat.and an FE of 15.56%,which are approximately 5 and 3 times greater,respectively,than those of pure NiO nanosheets at the same applied potential.X‐ray photoelectron spectroscopy analysis revealed that Pt in Pt/NiO‐NSs exist as Pt0,Pt^(2+),and Pt^(4+)and that high‐valence Pt ions are more electropositive,thereby favoring chemisorption and the activation of N2 molecules.Density function theory calculations showed that the d‐band of Pt nanoparticles supported on NiO is significantly tuned compared to that of pure Pt,affording a more favorable electronic structure for NRR.The results of this study show that Pt can be an effective NRR electrochemical catalyst when loaded on an appropriate substrate.Most importantly,it provides a new synthetic avenue for the fabrication of highly active Pt‐based NRR electrocatalysts.

A facile strategy for ultrasmall Pt NPs being partiallyembedded in N-doped carbon nanosheet structure for efficient electrocatalysis

A facile strategy is established for constructing composite nanostructure with ultrasmall Pt nanoparticles(NPs) of ~2 nm in diameter being homogeneously embedded in N-doped carbon nanosheets. The strong coordination between Pt atoms in cisplatin and N atoms in pyrrole contributes to the robust embedding of Pt NP into the N-doped carbon nanosheets after annealing. Such a unique partially-embedding structure facilitates the active site exposure while stabilizing the ultrasmall Pt NPs, leading to the comparable electrochemical activities for hydrogen evolution and oxygen reduction reactions, and substantially improves durability performance compared to that of the state-of-the-art Pt/C(20 wt%).

Controlled Synthesis and Growth of Perfect Platinum Nanocubes Using a Pair of Low-Resistivity Fastened Silicon Wafers and Their Electrocatalytic Properties

Perfect platinum （Pt） nanocubes with high density have been synthesized by controlled reduction of hexachloroplatinic acid in the presence of H2SO4 and HCl, employing a pair of low-resistivity fastened silicon （FS） wafers at room temperature. The presence of the additive charges （induced by prior etching of the silicon surface with HF to remove any SiO2 layer） between the interfaces of the FS surface results in a high charge density and facilitates fast deposition of Pt nanoparticles via electroless plating. The charge density, stirring time, and homogeneity of the aqueous solution influenced the geometrical shapes of the Pt nanoparticles. The parameters were finely tuned in order to control the nucleation and growth rates and obtain perfect Pt nanocubes. The perfect Pt nanocubes were single crystalline with exposed {100} facets. Per equivalent Pt surface areas, the perfect Pt nanocubes showed enhanced catalytic activity relative to truncated Pt nanocubes or spherical Pt nanoparticles for the electrooxidation of liquid feed fuels such as methanol and ethanol. Moreover, there a strong correlation was observed between the optical, electrical, thermal, magnetic, and catalytic properties of the perfect Pt nanocubes which should lead to a variety of technological applications of these materials.