Molecular Photoelectrodes with Enhanced Photogenerated Charge Transport for Efficient Solar Hydrogen Evolution.

Photoelectrocatalytic cells for seawater splitting have shown promise toward large-scale deployment; however, challenges remain in operation performances, which outline clear research needs to scale up photoelectrodes with small loss of efficiency. Here, we report an approach for scalable and robust solar H evolution by enhancing photogenerated charge transport in a H-evolving molecular photoelectrode. The photoelectrode is based on p-type conjugated polymers that are homogeneously distributed in a polycarbazole network.

Molecular Conjugated-Polymer Electrode Enables Rapid Proton Conduction for Electrosynthesis of Ammonia from Nitrate.

Electrosynthesis of ammonia (NH) from nitrate (NO ) using renewable energy holds promise as a supplementary alternative to the Haber-Bosch process for NH production. Most research focuses on tuning the catalytic activity of metal catalysts by modification of the catalyst structures. However, the electrode supports which could influence the catalytic activity have not been well-explored.

Static Organic p-n Junctions in Photoelectrodes for Solar Ammonia Production with 86 % Internal Quantum Efficiency.

For photoelectrocatalytic cells, a limitation exists in finding appropriate photoelectrode configurations that couple efficient extraction of high-energy electrons from absorbed photons and selective catalysis. Here we report an organic p-n junction approach to fabricate molecular photoelectrodes for conversion of solar energy and nitrate into valuable ammonia product. Solar irradiation of the photoelectrode generates charge-separated states with electrons and holes spatially separated at the n-type and p-type components, as revealed by surface photovoltage mapping, at a quantum yield of 90 %.

Molecular Wiring of Electrocatalytic Nitrate reduction to Ammonia and Water Oxidation by Iron-Coordinated Macroporous Conductive Networks.

Developing stable electrocatalysts with accessible isolated sites is desirable but highly challenging due to metal agglomeration and low surface stability of host materials. Here we report a general approach for synthesis of single-site Fe electrocatalysts by integrating a solvated Fe complex in conductive macroporous organic networks through redox-active coordination linkages. Electrochemical activation of the electrode exposes high-density coordinately unsaturated Fe sites for efficient adsorption and conversion of reaction substrates such as NO and HO.

Charge Photoaccumulation in Covalent Polymer Networks for Boosting Photocatalytic Nitrate Reduction to Ammonia.

In the design of photoelectrocatalytic cells, a key element is effective photogeneration of electron-hole pairs to drive redox activation of catalysts. Despite recent progress in photoelectrocatalysis, experimental realization of a high-performance photocathode for multi-electron reduction of chemicals, such as nitrate reduction to ammonia, has remained a challenge due to difficulty in obtaining efficient electrode configurations for extraction of high-throughput electrons from absorbed photons. This work describes a new design for catalytic photoelectrodes using chromophore assembly-functionalized covalent networks for boosting eight-electron reduction of nitrate to ammonia.

Enhanced 3-D asynchronous correlation data preprocessing method for Raman spectroscopy of Chinese handmade paper.

We have developed a novel 3D asynchronous correlation method (3D-ACM) designed for the classification and identification of Chinese handmade paper samples using Raman spectra and machine learning. The 3D-ACM approach involves two rounds of tensor product and Hilbert transform operations. In the tensor product process, the outer product of the spectral data from different samples within the same category is computed, establishing inner connections among all samples within that category.

Molecular Self-Assembly in Conductive Covalent Networks for Selective Nitrate Electroreduction to Ammonia.

Electrochemical nitrate (NO) reduction in aqueous media provides a useful approach for ammonia (NH) synthesis. While efforts are focused on developing catalysts, the local microenvironment surrounding the catalyst centers is of great importance for controlling electrocatalytic performance. Here, we demonstrate that a self-assembled molecular iron catalyst integrated in a free-standing conductive hydrogel is capable of selective production of NH from NO at efficiencies approaching unity.