| 1. |
- Xu, Suxian, et al.
(författare)
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Polystyrene spheres-templated mesoporous carbonous frameworks implanted with cobalt nanoparticles for highly efficient electrochemical nitrate reduction to ammonia
- 2023
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Ingår i: Applied Catalysis B. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 323
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Tidskriftsartikel (refereegranskat)abstract
- Electrocatalytic nitrate reduction reaction (eNO3RR) to ammonia (NH3) provides an intriguing approach for both environmental denitrification and sustainable NH3 synthesis. Herein, we report the fabrication of hierarchically mesoporous Co nanoparticles decorated N-doped carbon composites as a highly efficient electrocatalyst for eNO3RR by using monodispersed polystyrene spheres (PS) as sacrificial templates (MR Co-NC). By taking advantage of the large specific area of the pore-rich structures and the high intrinsic activity of metallic Co, the MR Co-NC shows remarkable activity toward eNO3RR, which achieves a partial current density of 268 mA cm-2 with a Faradaic efficiency (FE) of 95.35 +/- 1.75 % and a generation rate of 1.25 +/- 0.023 mmol h-1 cm-2 for NH3 production under the optimal conditions. The porous carbon skeleton was found to play a dual role by simul-taneously protecting the active sites from oxidation and facilitating long-range charge and mass transfer. Theoretical calculations reveal a lower energy barrier of the rate-determining step (*NO2 + H2O + 2e- -> *NO + 2OH-) on the metallic Co of MR Co-NC over beta-Co(OH)2 formed by the reconstruction of carbon-free Co nanoparticles.
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| 2. |
- Liu, Guoquan, et al.
(författare)
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Photocatalytic Water Oxidation by Surface Modification of BiVO4 with Heterometallic Polyphthalocyanine
- 2023
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 13:13, s. 8445-8454
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Tidskriftsartikel (refereegranskat)abstract
- Developing efficient photocatalysts for water oxidation is among the central challenges of solar energy conversion. Here, we report semiconductor-molecular photocatalysts by integration of heteronuclear bimetallic polyphthalocyanine (PPc) catalysts with particulate bismuth vanadate (BiVO4) as the photosensitizer. Their photocatalytic activity for water oxidation was modulated by tuning the Fe/Co ratio of polyphthalocyanines. At an optimal Fe/Co ratio of 3:1, the resulting Fe3CoPPc-BiVO4 hybrid exhibits an excellent oxygen evolution rate of 4557 μmol g-1 h-1 in the presence of iodate under visible light irradiation, which is nearly two orders of magnitude greater than that of pristine BiVO4 and superior to those of the corresponding homometallic counterparts. Both experimental and theoretical methods suggest that the presence of a large population of high-valent Fe/Co molecular species due to the favorable interfacial charge transfer and upshift of the d-band centers of metal sites toward Fermi level lead to a lower energy barrier for the O-O bond formation and eventually promote the oxidation of water.
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| 3. |
- Yu, Suxian, et al.
(författare)
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Modulating the proton transfer kinetics via Ru single atoms for highly efficient ammonia synthesis
- 2023
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Ingår i: Chem Catalysis. - : Elsevier BV. - 2667-1107 .- 2667-1093. ; 3:9
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical nitrate reduction reaction (eNO3RR) is an appealing technology for converting environmentally toxic NO3− to ammonia (NH3). This approach was usually obstructed by the multi-proton/electron involved process. Here, we report a catalyst with Ru single atoms supported on Co3O4 (Ru SAs-Co3O4). The as-developed Ru SAs-Co3O4 catalyst shows a remarkable NH3-evolving activity with a faradic efficiency of 94.92% ± 4.02% at the potential of −0.2 V (vs. RHE) and a generation rate of 1,843.45 ± 57.14 μmol h−1 cm−2 at the potential of −0.5 V. Further investigations revealed that the Ru SAs play a dual role in simultaneously accelerating the proton transfer and modulating the d-electron structures of the neighboring Co sites, which led to a lower energy barrier of the rate-determining step. Eventually, by combining the eNO3RR and electrosynthesis of 5,5′-azotetrazolate at a two-electrode system, an energy-saving NH3 synthesis, while simultaneously producing value-added chemicals, was successfully achieved.
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