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Supramolecular chemistry during the synthesis of carbon-nitrogen-based materials has recently experienced a renaissance in the arena of photocatalysis and electrocatalysis. In this review, we start with the discussion of supramolecular assemblies-derived carbon-nitrogen-based materials’ regulation from the aspect of morphology, chemical composition, and micro/nanostructural control. Afterwards the recent advances of these materials in energy and environment related applications, including degradation of pollutants, water splitting, oxygen reduction reactions, CO2 reduction reactions along with organic synthesis are summarized. The correlations between the structural features and physicochemical properties of the carbon-nitrogen-based materials and the specific catalytic activity are discussed in depth. By highlighting the opportunities and challenges of supramolecular assembly strategies, we attempt an outlook on possible future developments for highly efficient carbon-based photo/electrocatalysts.

Bi-based metal-organic frameworks (Bi-MOFs) as efficient catalysts for the CO2 electroreduction reaction (CRR) have been extensively investigated. It has been established that Bi-MOFs usually undergo in-situ transformation during the CRR, ultimately converting into Bi nanostructures. However, the effect of the MOF precursors on the structure of the derived Bi catalysts and consequently on their electrocatalytic properties has not been clearly elucidated. In this work, we prepared four variants of a novel Bi-MOF with different morphologies and dimensions, and explored the effects of the precursors on the resulting Bi catalysts and their CRR performance. A precursor-dependent in-situ transformation and its profound impact on tuning the CO2-formate FE towards ∼100% have been revealed. Among the four examined variants, Bi-MOF with nanocube-like morphology (BiMOF-NC) is transformed into thin and flat Bi nanosheets capable of successfully enveloping the fibers of carbon paper (working electrode), while the other three variants with increased size and dodecahedral/octahedral geometry have been transformed into Bi nanoflowers, exposing a fair portion of the carbon fibers in the working electrode. Furthermore, the transformation rate was found to be dependent on the precursors and BiMOF-NC exhibited the highest rate of reconstruction compared with other samples. Consequently, the Bi catalyst derived from BiMOF-NC delivered a selectivity for the formate product of nearly 100% at −1.2 V (vs. reversible hydrogen electrode (RHE)) and of over 95% in a wide potential range due to efficient suppression of the competing hydrogen evolution reaction (HER) over carbon fibers. The in-situ transformed BiMOF-NC also demonstrated equivalently high formate selectivity at large current densities (≽100 mA cm−2) in flow cell reactors as that in H-type reactors, underscoring its potential for industrial applications. This work highlights the necessity of finely tuning the structural features of MOF precursors to achieve optimized electrocatalytic performance. [ABSTRACT FROM AUTHOR]

Construction of a built-in electric field has been identified as an attractive improvement strategy for photoelectrochemical (PEC) water splitting by facilitating the carrier extraction from the inside to the surface. However, the promotion effect of the electric field is still restrained by the confined built-in area. Herein, we construct a microscale built-in electric field via gradient oxygen doping. The octahedral configuration of the synthesized CdIn 2 S 4 (CIS) provides a structural basis, which enables the subsequent oxygen doping to reach a depth of ∼100 nm. Accordingly, the oxygen-doped CIS (OCIS) photoanode exhibits a microscale built-in electric field with band bending. Excellent PEC catalytic activity with a photocurrent density of 3.69 mA cm -2 at 1.23 V vs. RHE is achieved by OCIS, which is 3.1 times higher than that of CIS. Combining the results of thorough characterization and theoretical calculations, accelerating migration and separation of charge carriers have been determined as the reasons for the improvement. Meanwhile, the recombination risk at the doping centers has also been reduced to the minimum via optimal experiments. This work provides a new-generation idea for constructing a built-in electric field from the view point of bulky configuration towards PEC water splitting.