Ru‐Pincer Complex‐Bridged Cu‐Porphyrin Polymer for Robust (Photo)Electrocatalytic H₂ Evolution via Single‐Atom Active Sites

Abstract

Organic polymers have attracted much attention in the field of energy conversion owing to their excellent tailoring ability via heterometal incorporation and/or functionalization. Herein, a novel pincer complexbridged porphyrin polymer is synthesized using Cu-porphyrin (CuPor) and Ru-N′NN′-pincer complex (RuN 3 ) as monomers. The resultant CuPor-RuN 3 polymer delivers robust electrocatalytic hydrogen evolution reaction (HER) performance with outstanding durability and ultralow overpotentials of 73 and 114 mV at a current density of 10 mA cm -2 in acidic and alkaline media, respectively. Moreover, the CuPor-RuN 3 polymer displays great potential to fabricate photoelectrochemical (PEC) cells with a BiVO 4 photoanode, where the additional photoinduced electrons from CuPor-RuN 3 endow the BiVO 4 ||CuPor-RuN 3 PEC cell with much better activity for overall water splitting than the BiVO 4 ||Pt/C one, demonstrating that CuPor-RuN 3 would be a promising (photo)electrocatalyst to replace the benchmark Pt/C. The experimental and theoretical studies reveal that the Cu/Ru heterobimetallic centers in the polymer not only enhance the inherent electron transfer from Cu sites to Ru ones that serve as singleatom catalytic sites (Ru-N 3 ), but also efficiently regulate the electronic property of the Ru-N 3 sites, and thus boosting (photo)electrocatalytic HER activity. The proposed strategy opens a new avenue to fabricate porphyrinbased polymers with heteromultimetallic centers as effective HER (photo)electrocatalysts.

Efficient CO2 reduction over a Ru-pincer complex/TiO2 hybrid photocatalyst via direct Z-scheme mechanism

“…2d. As seen, the C 1s spectra display four BE peaks at 284.6, 285.8, 286.6, and 287.9 eV (for the Ru(N 3 )(ONO)), and at 284.6, 285.8, 286.8, and 288.9 eV (for the Ru(N 3 )(ONO)/TiO 2 ), which can be ascribed to the C 1s species in aromatic carbon (C–C/CC), C–N in nitrogen heterocyclic ring, phenolic hydroxyl (C–OH), and carboxylic (–COO) groups, 34,39,40 respectively. Besides, the BE peak at 292.3 eV for the Ru(N 3 )(ONO) can be ascribed to the shake-up satellite originated from the π–π* interactions, 41,42 and that at 292.8 eV for the Ru(N 3 )(ONO)/TiO 2 is attributed to the PTFE (–(CF 2 ) n –).…”

“…2d) can be deconvoluted into two BE peaks at 281.1 (Ru3d 5/2 ) and 285.2 (Ru3d 3/2 ), suggesting the oxidation state of Ru in the Ru(N 3 )(ONO) complex is +2. 38,39 The high-resolution C 1s spectra of the Ru(N 3 )(ONO) complex and Ru(N 3 )(ONO)/TiO 2 hybrid material are also shown in Fig. 2d.…”

Single-atom catalysts for high-efficiency photocatalytic and photoelectrochemical water splitting: distinctive roles, unique fabrication methods and specific design strategies

“…The fabrication routes of SACs for photocatalytic and photoelectrochemical water splitting play a highly crucial role in anchoring SAs on the substrate to achieve superior lightharvesting and charge carrier transport/separation capability, abundant active sites for surface redox reactions and excellent photo(electro)catalytic activity. 56,96,130,[150][151][152][153] The unique fabrication routes of SACs are summarized and discussed in this section and the comparison of fabrication methods for SACs and typical NP-based photocatalysts as well as various synthesis routes of SACs applied in photo(electro)catalysis, electrocatalysis and heterogeneous catalysis is also presented and discussed in detail.…”

Recent progress on the long‐term stability of hydrogen evolution reaction electrocatalysts

“…67 Moreover, due to the scarcity of precious metal resources and high preparation technology costs, the long-term development goal is to effectively improve the utilization efficiency of precious metal atoms, reduce metal load and stabilize metal sites to ensure high activity and stability. Investigations with the target toward improvements on the catalytic stability of those precious metals for hydrogen evolution have been reported through the alloying with other metals, 68 spacing confinements, 69 metal-support interaction through anchoring, fixing precious metals on functional supports, 70 and the local regulations of coordination environment. 71…”