Pt–Pd alloy nano-catalysts supported on TiO2 were developed to enable efficient light-induced photocatalytic N-alkylation of amines with alcohols. Various techniques such as BET, XRD, XPS, HRTEM, UV-vis DRS, and PL analysis were utilized to characterize the catalysts. The photocatalytic mechanism was discussed based on observation as well as theoretical calculation. It was found that Pt serves as a hydrogen shuttle, extracting hydrogen from alcohols to Pd for subsequent hydrogenation on the Pd site. By changing the Pd/Pt ratio, it is feasible to tune the reaction rates of methanol dehydrogenation and imine hydrogenation simultaneously, resulting in an efficient N-alkylation reaction. As a result, the optimum catalyst Pd1Pt1/TiO2 exhibits excellent catalytic performance which is superior to the previously reported ones in terms of both the catalytic efficiency and the production capacity.
Jinlong Li,Huiyuan Liu,Weiqi Zhang,Qian Xu,Sae Youn Lee,Narayanamoorthy Bhuvanendran,Huaneng Su
The catalyst layer (CL) is the only electrochemical reaction site in proton exchange membrane fuel cells (PEMFCs), decisive in their performance. Herein, a mild and simplified strategy is implemented into the in-situ growth of Pt–Pd alloy catalysts on the gas diffusion layer (GDL) as the CLs for PEMFCs. Pt/C is used as the nucleation site to assist the in-situ growth of the Pt–Pd CL. The as-prepared Pt–Pd CL behaves as a multi rhombic-pyramidal structure, which are evenly distributed on the GDL surface. The effect of the Pt/Pd atomic ratio on the electrocatalytic activity is investigated through a single-cell performance test, and the optimal atomic ratio is determined to be 1/2, which exhibits excellent cell performance and low activation polarization loss. Meanwhile, the single-cell test results reveal that Pt 1 Pd 2 CL reaches optimal performance at a loading of 0.122 mg cm −2 (∼0.06 mg Pt cm −2 ), with a peak Pt-specific power density of 14.23 W mg −1 (6.81 W mg −1 in PtPd), approximately 3.96 times that of a commercial Pt/C CL (0.2 mg Pt cm −2 ). Furthermore, Pt 1 Pd 2 CL shows significantly better stability than the commercial Pt/C CL, indicating that the in-situ preparation of the Pt-based CL has an excellent prospect for the commercial development of PEMFCs.
Wang Xiaoying,Yuan Wei,Kuang Yijing,Chen Xuyuan,Wang Xiaoning,Zhang Xiaoyu
A ratiometric electrochemical immunosensor is proposed for simultaneous detection of cellular-myelocytomatosis oncoprotein (C-myc) and B-cell lymphoma 2 (Bcl-2) via the potential-resolved strategy. It relied on multi-role co-loaded alloy composites (CLACs) and poly(3,4-ethylenedioxythiophene) (PEDOT)-graphene oxide (GO)-multiwalled carbon nanotubes (MWCNTs) (PGM) modified electrodes. CLACs with good catalytic and enzyme-like properties were synthesized in one step by loading tetramethylbenzidine (TMB) or methylene blue (MB) into Pt-Pd alloy and used as label materials. After immunological reactions, CLACs showed distinguishable dual differential pulse voltammetry signals at − 0.26 V and 0.38 V, corresponding to C-myc and Bcl-2, and the PGM had an electrochemical signal at 1.2 V, which could be used as a reference signal to construct a ratiometric sensor. CLACs had a satisfactory synergistic effect with the PGM, and eventually achieved quadruple signal amplification. Thus, benefiting from multiple magnification and ratiometric self-calibration functions, sensitive detections of C-myc and Bcl-2 were achieved, with detection limits as low as 0.5 and 2.5 pg mL −1 , respectively. Additionally, when the designed method was applied to blood samples from lymphoma patients, results consistent with the ELISA kit were obtained. This will open avenues for constructing multiple protein detection sensors. Graphical abstract
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