The surface plasmon resonance (SPR) induced photothermal and photoelectrocatalysis effects are crucial for catalytic reactions in many areas. However, it is still difficult to distinguish these two effects quantitatively. Here we used surface-enhanced Raman scattering (SERS) to detect the photothermal and photoelectrocatalytic effects induced by SPR from Au core Pt shell Nanoparticles (Au@Pt NPs), and calculated the quantitative contribution of the ratio of the photothermal and photoelectrocatalysis effects towards the catalytic activity. The photothermal effect on the nanoparticle surface after illumination is detected by SERS. The photoelectrocatalytic effect generated from SPR is proved by SERS with a probe molecule of p-aminothiophenol (PATP).
Low-cost, non-noble-metal electrocatalysts are required for direct methanol fuel cells,b ut their development has been hindered by limited activity,high onset potential, low conductivity,a nd poor durability.Asurface electronic structure tuning strategy is presented, which involves doping of aforeign oxophilic post-transition metal onto transition metal aerogels to achieve an on-noble-metal aerogel Ni 97 Bi 3 with unprecedented electrocatalytic activity and durability in methanol oxidation. Trace amounts of Bi are atomically dispersed on the surface of the Ni 97 Bi 3 aerogel, which leads to an optimum shift of the d-band center of Ni, large compressive strain of Bi, and greatly increased conductivity of the aerogel. The electrocatalyst is endowed with abundant active sites, efficient electron and mass transfer,r esistance to CO poisoning, and outstanding performance in methanol oxidation. This work sheds light on the design of high-performance non-noblemetal electrocatalysts.
Photocatalysis is a promising technology for renewable energy production. Many photocatalysis have realized the visible-light-driven catalytic activity. However, it is still difficult to achieve the enhanced photocatalytic activity with tunable wavelength. We have designed tunable wavelength enhanced photoelectrochemical cells by tuning the surface plasmon resonance (SPR) peaks, which can be controlled by the aspect ratios of the Au nanorods, for both the cathode with the hydrogen evolution reaction and the anode with the electrooxidation of methanol reaction. The optimal photocatalytic activity of the hydrogen evolution and electrooxidation of the methanol can be realized only when the illuminating wavelength matches with the SPR peaks, which is quite selective to the illuminating wavelength. The blue shift of the SPR peak increases the photoelectrocatalytic effect whereas the red shift enhances the photothermal effect. Such studies provide a useful way for improving the photocatalytic activity and the selectivity of the photocatalytic reactions by adjusting the illuminating wavelength.
Insufficient catalytic activity and stability and high cost are the barriers for Pt‐based electrocatalysts in wide practical applications. Herein, a hierarchically porous PtNi nanoframe/N‐doped graphene aerogel (PtNiNF‐NGA) electrocatalyst with outstanding performance toward methanol oxidation reaction (MOR) in acid electrolyte has been developed via facile tert‐butanol‐assisted structure reconfiguration. The ensemble of high‐alloying‐degree‐modulated electronic structure and correspondingly the optimum MOR reaction pathway, the structure superiorities of hierarchical porosity, thin edges, Pt‐rich corners, and the anchoring effect of the NGA, endow the PtNiNF‐NGA with both prominent electrocatalytic activity and stability. The mass and specific activity (1647 mA mgPt−1, 3.8 mA cm−2) of the PtNiNF‐NGA are 5.8 and 7.8 times higher than those of commercial Pt/C. It exhibits exceptional stability under a 5‐hour chronoamperometry test and 2200‐cycle cyclic voltammetry scanning.
Toughness
improvement of thermosetting benzoxazine (BZ) /epoxy
(ER) blends is of great significance to expand their applications
in the field of high-performance structural parts. Introduction of
multiphase structures to the thermosetting blends via in situ reaction
induced phase separation is a promising way to improve their toughness.
However, the influences of the blend compositions on the phase separation
and phase morphology as well as the thermal and mechanical properties
of blends are still not clear. Here, we prepared a variety of BZ/ER/imidazole
(MZ) ternary blending systems with different compositions and found
that phase separation structures, including sea-island, cocontinuous,
and phase-inversion morphologies, could be controlled by tuning the
composition of ER resins and MZ. At a specific composition of ER resins,
increasing the MZ content is prone to form phase separation structures,
and the minimum MZ content needed for phase separation increased with
the ER content. What is more, when the reactivity difference between
BZ and ER (ΔEα) was larger than 40%,
phase separation could occur. Finally, the introduction of multiphase
morphologies significantly improved the impact strength and well maintained
the thermomechanical properties of ternary blends.
Designing cost‐effective, highly active, and durable platinum (Pt)‐based electrocatalysts is a crucial endeavor in electrochemical hydrogen evolution reaction (HER). Herein, the low‐content Pt (0.8 wt%)/tungsten oxide/reduced graphene oxide aerogel (LPWGA) electrocatalyst with excellent HER activity and durability is developed by employing a tungsten oxide/reduced graphene oxide aerogel (WGA) obtained from a facile solvothermal process as a support, followed by electrochemical deposition of Pt nanoparticles. The WGA support with abundant oxygen vacancies and hierarchical pores plays the roles of anchoring the Pt nanoparticles, supplying continuous mass transport and electron transfer channels, and modulating the surface electronic state of Pt, which endow the LPWGA with both high HER activity and durability. Even under a low loading of 0.81 μgPt cm−2, the LPWGA exhibits a high HER activity with an overpotential of 42 mV at 10 mA cm−2, an excellent stability under 10000‐cycle cyclic voltammetry and 40 h chronopotentiometry at 10 mA cm−2, a low Tafel slope (30 mV dec−1), and a high turnover frequency of 29.05 s−1 at η = 50 mV, which is much superior to the commercial Pt/C and the low‐content Pt/reduced graphene oxide aerogel. This work provides a new strategy to design high‐performance Pt‐based electrocatalysts with greatly reduced use of Pt.
Low-cost, non-noble-metal electrocatalysts are required for direct methanol fuel cells,b ut their development has been hindered by limited activity,high onset potential, low conductivity,a nd poor durability.Asurface electronic structure tuning strategy is presented, which involves doping of aforeign oxophilic post-transition metal onto transition metal aerogels to achieve an on-noble-metal aerogel Ni 97 Bi 3 with unprecedented electrocatalytic activity and durability in methanol oxidation. Trace amounts of Bi are atomically dispersed on the surface of the Ni 97 Bi 3 aerogel, which leads to an optimum shift of the d-band center of Ni, large compressive strain of Bi, and greatly increased conductivity of the aerogel. The electrocatalyst is endowed with abundant active sites, efficient electron and mass transfer,r esistance to CO poisoning, and outstanding performance in methanol oxidation. This work sheds light on the design of high-performance non-noblemetal electrocatalysts.
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