Approximately 2% of the energy consumed by humans each year is used to make nitrogen-based fertilizers, with ammonia (NH3) production being the most significant contributor to this energy demand. C...

Defect Engineering in Photocatalytic Nitrogen Fixation

Heterojunction photocatalyst fabrication benefits the improvement of photocatalytic activity. However, the influence of different coupling facets receives less attention. Herein, two p-n junctions with different coupling facets of BiOI, denoted as B001/CN002 and B110/CN002+, were constructed by a simple precipitation method. In B001/CN002, BiOI nanosheets parallel combined with g-C3N4 with the {001} facet of BiOI and (002) plane of g-C3N4. After being treated by CTAB, the (002) plane of g-C3N4 shows positive charge (g-C3N4+), and the BiOI nanosheets were vertically assembled onto g-C3N4+. The results of photodegradation on multiform industrial contaminants and antibiotic revealed that B001/CN002 shows much higher photoactivity than g-C3N4, g-C3N4+, BiOI and B110/CN002+. The substantially facilitated charge separation and transfer at the interface of B001/CN002 promote the generation of 1O2 and O2−, accounting for the excellent photocatalytic activity. The study may provide a new perspective on designing heterostructured photocatalytic materials via facet-charge-induced interfacial engineering strategy.

Facet-charge-induced coupling dependent interfacial photocharge separation: A case of BiOI/g-C3N4 p-n junction

Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

Photoelectrochemical (PEC) water splitting is considered as a promising technology for producing clean energy such as hydrogen. The urgent challenge in this field is how to prepare highly efficient electrode materials. The introduction of oxygen vacancies (OVs) into catalytic materials has been confirmed to be an effective strategy toward enhancing the performance of PEC water splitting by both theoretical calculations and experiment results. Herein, the existing strategies for introducing OVs into nanomaterials are discussed in this minireview. In addition, the effect of OVs on PEC water splitting to improve the light absorption efficiency, charges transfer efficiency, and charge injection efficiency was summarized. Finally, we propose several challenges that need to be addressed in the field of PEC water splitting in the future. This minireview could offer some important contributions to the future synthesis of nanomaterials with rich OVs for PEC application. 

Oxygen Vacancy-Based Metal Oxides Photoanodes in Photoelectrochemical Water Splitting

Global energy and environmental crises are among the most pressing challenges facing humankind. To overcome these challenges, recent years have seen an upsurge of interest in the development and production of renewable chemical fuels as alternatives to the nonrenewable and high-polluting fossil fuels. Photocatalysis, photoelectrocatalysis, and electrocatalysis provide promising avenues for sustainable energy conversion. Single- and dual-component catalytic systems based on nanomaterials have been intensively studied for decades, but their intrinsic weaknesses hamper their practical applications. Multicomponent nanomaterial-based systems, consisting of three or more components with at least one component in the nanoscale, have recently emerged. The multiple components are integrated together to create synergistic effects and hence overcome the limitation for outperformance. Such higher-efficiency systems based on nanomaterials will potentially bring an additional benefit in balance-of-system costs if they exclude the use of noble metals, considering the expense and sustainability. It is therefore timely to review the research in this field, providing guidance in the development of noble-metal-free multicomponent nanointegration for sustainable energy conversion. In this work, we first recall the fundamentals of catalysis by nanomaterials, multicomponent nanointegration, and reactor configuration for water splitting, CO2 reduction, and N-2 reduction. We then systematically review and discuss recent advances in multicomponent-based photocatalytic, photo-electrochemical, and electrochemical systems based on nanomaterials. On the basis of these systems, we further laterally evaluate different multicomponent integration strategies and highlight their impacts on catalytic activity, performance stability, and product selectivity. Finally, we provide conclusions and future prospects for multicomponent nanointegration. This work offers comprehensive insights into the development of cost-competitive multicomponent nanomaterial-based systems for sustainable energy-conversion technologies and assists researchers working toward addressing the global challenges in energy and the environment.

Noble-Metal-Free Multicomponent Nanointegration for Sustainable Energy Conversion.

In-situ approach to fabricate BiOI photocathode with oxygen vacancies: Understanding the N2 reduced behavior in photoelectrochemical system

Understanding the key role of vanadium in p-type BiVO4 for photoelectrochemical N2 fixation

In situ constructing intramolecular ternary homojunction of carbon nitride for efficient photoinduced molecular oxygen activation and hydrogen evolution

NH3 is mainly obtained by the Haber-Bosch method in the process of industrial production, which is not only accompanied by huge energy consumption but also environmental pollution. The reduction of N2 to NH3 under mild conditions is an important breakthrough to solve the current energy and environmental problems, so the preparation of catalysts that can effectively promote the reduction of N2 is a crucial step. In this work, BiVO4 decorated with amorphous MnCO3/C double layers has been successfully synthesized by a one-step method for the first time. The C and MnCO3 have been formed as ultrathin film, which enables the establishment of a uniform and tight interface with BiVO4. The temperature-programmed desorption of N2 (N2-TPD) spectra confirmed that the MnCO3/C could endow BiVO4 with a drastic enhancement of the chemical absorption ability of a N2 molecule compared with the pristine BiVO4. Meanwhile, the method of isotope labeling proved that the catalyst exhibited excellent selectivity for the photocatalytic nitrogen reduction reaction (NRR). The production rate of NH3 up to 2.426 mmol m-2 h-1 has been achieved over the BiVO4/MnCO3/C, which is almost 8 times that of pristine BiVO4. The promoted production rate of NH3 over BiVO4/MnCO3/C could be mainly attributed to the cooperative process between MnCO3 and C amorphous layers. Therefore, this work could provide an alternative insight to understand the NRR process based on the model of a hierarchical amorphous structure.

Yajie Bai

Papers

In-situ approach to fabricate BiOI photocathode with oxygen vacancies: Understanding the N2 reduced behavior in photoelectrochemical system

Understanding the key role of vanadium in p-type BiVO4 for photoelectrochemical N2 fixation

In situ constructing intramolecular ternary homojunction of carbon nitride for efficient photoinduced molecular oxygen activation and hydrogen evolution

Amorphous MnCO3/C Double Layers Decorated on BiVO4 Photoelectrodes to Boost Nitrogen Reduction.

Charge-transfer dynamics at a Ag/Ni-MOF/Cu2O heterostructure in photoelectrochemical NH3 production.