Biocompatible Electrochemical Sensor Based on Platinum-Nickel Alloy Nanoparticles for In Situ Monitoring of Hydrogen Sulfide in Breast Cancer Cells

Hydrogen sulfide (H2S), an endogenous gasotransmitter, is produced in mammalian systems and is closely associated with pathological and physiological functions. Nevertheless, the complete conversion of H2S is still unpredictable owing to the limited number of sensors for accurate and quantitative detection of H2S in biological samples. In this study, we constructed a disposable electrochemical sensor based on PtNi alloy nanoparticles (PtNi NPs) for sensitive and specific in situ monitoring of H2S released by human breast cancer cells. PtNi alloy NPs with an average size of 5.6 nm were prepared by a simple hydrothermal approach. The conversion of different forms of sulfides (e.g., H2S, HS−, and S2−) under various physiological conditions hindered the direct detection of H2S in live cells. PtNi NPs catalyze the electrochemical oxidation of H2S in a neutral phosphate buffer (PB, pH 7.0). The PtNi-based sensing platform demonstrated a linear detection range of 0.013–1031 µM and the limit of detection was 0.004 µM (S/N = 3). Moreover, the PtNi sensor exhibited a sensitivity of 0.323 μA μM−1 cm−2. In addition, the stability, repeatability, reproducibility, and anti-interference ability of the PtNi sensor exhibited satisfactory results. The PtNi sensor was able to successfully quantify H2S in pond water, urine, and saliva samples. Finally, the biocompatible PtNi electrode was effectively employed for the real-time quantification of H2S released from breast cancer cells and mouse fibroblasts.

PtNi Alloy Coated in Porous Nitrogen-Doped Carbon as Highly Efficient Catalysts for Hydrogen Evolution Reactions

The development of low platinum loading hydrogen evolution reaction (HER) catalysts with high activity and stability is of great significance to the practical application of hydrogen energy. This paper reports a simple method to synthesize a highly efficient HER catalyst through coating a highly dispersed PtNi alloy on porous nitrogen-doped carbon (MNC) derived from the zeolite imidazolate skeleton. The catalyst is characterized and analyzed by physical characterization methods, such as XRD, SEM, TEM, BET, XPS, and LSV, EIS, it, v-t, etc. The optimized sample exhibits an overpotential of only 26 mV at a current density of 10 mA cm−2, outperforming commercial 20 wt% Pt/C (33 mV). The synthesized catalyst shows a relatively fast HER kinetics as evidenced by the small Tafel slope of 21.5 mV dec−1 due to the small charge transfer resistance, the alloying effect between Pt and Ni, and the interaction between PtNi alloy and carrier.

Low-Pt NiNC-supported PtNi nanoalloy oxygen reduction reaction electrocatalysts—In situ tracking of the atomic alloying process

Carbon-supported platinum-nickel (Pt-Ni) alloy nanoparticles (NPs) emerge as the electrocatalysts of choice for deployment in polymer electrolyte membrane fuel cell (PEMFC) cathodes. To date, viable PtNi nanoalloy catalysts are characterized by large Pt weight loading of up to 50 wt%. To a large extent, their preparation processes often involve the use of expensive or even hazardous organometallic metal precursors, solvents and capping agents, substantially limiting their synthetic scalability and sustainability. Here, we report a novel synthetic strategy toward highly active low-Pt loaded PtNi nanoalloy Oxygen Reduction Reaction (ORR) catalysts. The synthesis involves the Pyrolysis and Leaching of Ni-organic polymers, subsequent Pt nanoparticle Deposition followed by thermal Alloying (referred to as PLDA) to prepare single Ni atom site (NiNC)-supported bimetallic PtNi nanoalloy electrocatalysts with very low Pt weight contents of 3–5 wt% Pt loading. We demonstrate that despite this low Pt weight loading, the catalysts exhibit more favorable Pt-mass activities compared to conventional, carbon-supported 20–30 wt%Pt Pt-loaded benchmark PtNi alloy catalysts. Using in situ transmission electron microscopy, cyclic voltammetry, and surface CO stripping techniques, we track and unravel the key stages of the formation process of the PtNi nanoparticle catalysts directly at the atomic scale. By carefully chosen reference experiments, we find that carbon-encapsulated Ni NPs, rather than NiNx single sites, serve exclusively as the Ni atom source for PtNi alloy formation during thermal treatments. Our materials concepts offer a pathway to further decrease the overall Pt content of PEM fuel cell devices.

Selective Hydrogenation of the Carbonyls in Furfural and 5-Hydroxymethylfurfural Catalyzed by PtNi Alloy Supported on SBA-15 in Aqueous Solution Under Mild Conditions

Valuable furfuryl alcohol (FFA) and 2,5-dihydroxymethylfuran (DHMF) could be produced by selective hydrogenation of biomass-derived furfural (FF) and 5-hydroxymethylfurfural (HMF) with high atom economy. In this study, SBA-15 (a kind of mesoporous silica molecular sieve)-supported low metal loading (3 wt% total metal content) PtNi alloy catalyst (PtNi/SBA-15) was synthesized via two steps, including the generation of PtNi alloy by hydrothermal method, and the immobilization of PtNi alloy on SBA-15. PtNi/SBA-15 has ordered mesoporous structure with high surface area, and high dispersion of the PtNi alloy with the formation of Ptδ−-Niδ+ surface pairs on SBA-15, which benefit hydrogen activation and selective carbonyl hydrogenation. The selective hydrogenation of FF and HMF over PtNi/SBA-15 in water solvent at 303 K with 1.5 MPa H2 within 2 h, could respectively yield 64.6% FFA with 77.0% selectivity, and 68.2% DHMF with 81.9% selectivity. Besides, PtNi/SBA-15 exhibited a satisfactory water resistance and stability after recycling at least five runs.

Non-enzymatic sensor for determination of glucose based on PtNi nanoparticles decorated graphene

Diabetes has become a universal epidemic in recent years. Herein, the monitoring of glucose in blood is of importance in clinical applications. In this work, PtNi alloy nanoparticles homogeneously dispersed on graphene (PtNi alloy-graphene) was synthesized as a highly effective electrode material for glucose detection. Based on the modified PtNi alloy-graphene/glass carbon (PtNi alloy-graphene/GC) electrode, it is found that the PtNi alloy-graphene/GC electrode exhibited excellent electrocatalytic performance on glucose oxidation. Furthermore, the results from amperometric current–time curve show a good linear range of 0.5–15 mM with the limit of detection of 16 uM (S/N = 3) and a high sensitivity of 24.03 uAmM−1 cm−2. On account of the good selectivity and durability, the modified electrode was successfully applied on glucose detection in blood serum samples.