Sequential paired electrosynthesis capable of the production of organic chemicals through a series of electrochemical reactions that occur consecutively and in pairs are of high significance. Herein, a three-dimensional porous carbon felt-loaded PbO₂ electrode (PbO₂/CF) with a self-supported nanostructure was fabricated using a double-cathode electrodeposition method, which served as an efficient electrocatalyst enabling the unique sequential paired electrosynthesis of 1,4-hydroquinone (1,4-HQ) from phenol in a membrane-free electrolytic cell. In such an exotic paired electrolysis system, phenol is first oxidized to p-benzoquinone at the anode, which is subsequently reduced to 1,4-HQ at the cathode. The as-obtained PbO₂/CF electrode exhibited a remarkable electrochemical performance, achieving impressive conversion and selectivity of 94.5% and 72.1%, respectively, for the conversion of phenol to 1,4-HQ. This exceptional performance can be attributed to the open porous self-supported structure of the PbO₂/CF electrode, which improves the active site exposure and substrate adsorption capability and reduces mass and charge transfer resistance. Furthermore, the catalyst electrode well maintained its structure integrity even after 140 hours of long-term use, further highlighting its promising application for the electrosynthesis of 1,4-HQ. Moreover, this sequential paired electrosynthesis strategy can be further extended to other substrates with electron-withdrawing/donating groups over the PbO₂/CF electrode. The proof of concept in this innovative sequential paired electrosynthesis could provide a sustainable and efficient way to produce various desired organic compounds.

Exploring highly efficient Pt-free catalysts for hydrogen evolution reaction (HER) is of great importance for hydrogen (H₂) production. Herein, a novel HER electrocatalyst having abundant ultra-small (2–3 nm) Ru electronically confined by a B, N co-doped polar carbon surface (Ru/(B-N)-PC) was constructed. The Ru/(B-N)-PC catalyst exhibits a low overpotential of 15 mV at the current density of 10 mA·cm⁻², a low Tafel slope of 22.6 mV·dec⁻¹, and superior durability, which outperforms the benchmark Pt/C catalyst. Both experimental characterizations and theory calculations suggest that an electron communication established between B, N co-doped carbon surface and ultra-small Ru nanoparticles with electrons transferred from N atoms to Ru and back-transferred from Ru to B atoms, which exerts a moderate electronic modification of Ru. This, in turn, affords a modest H adsorption energy and a lower H₂O dissociation barrier, leading to the high-performance hydrogen evolution reaction. The work provides meaningful insight into the size control and electronic modulation of Ru catalyst for intrinsic HER activity improvement.

Heterogenized phthalocyanine-based molecular catalysts are the ideal electrocatalytic platforms for CO₂ reduction reaction (CO₂RR) because of their well-defined structures and potential properties. In addition to the pursuit of catalytic performances at industrial potentials, it is equally important to explore experimental rules and design considerations behind activity and selectivity. Herein, we successfully developed a series of nickel phthalocyanines (NiPcs) with different alkyl chains immobilized on multi-walled carbon nanotubes (CNT) to unveil the structure–performance relationship for electrocatalytic CO₂RR in neutral electrolyte. Interestingly, a volcano-type trend was found between the activity for CO₂-to-CO conversion and alkyl chain lengths of NiPcs on CNT. Experimental results further indicate that their electrocatalytic CO₂RR activities are highly related to the molecular dispersion and the heterointerfacial charge transfer capability adjusted by the alkyl chains. Particularly, the optimized electrocatalyst via accurate clipping at the molecular level exhibits an ultrahigh activity with Faradaic efficiency of CO up to 99.52%.