CuWO4 Hollow Nanospheres With Mo Clusters for Selective Nitrate Reduction
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Solution Overview
Problem
Existing electrochemical nitrogen reduction reaction (NO3RR) processes for converting nitrate to ammonia have low yield rates and are competitive with undesired hydrogen evolution reactions, necessitating the development of highly selective and efficient electrocatalysts.
Innovation Solution
The synthesis of CuWO4 hollow nanospheres with asymmetric oxygen vacancies and adjacent Mo clusters, achieved through a hydrothermal process, thermal treatment, plasma-treatment, and Mo cluster introduction, enhances the electrocatalytic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional Haber-Bosch process is used for nitrogen reduction, then high yield rate is achieved, but high temperature and pressure conditions are required with complicated chemical reactions
Solution Approach 1:
The patent replaces the mechanical/thermal system of Haber-Bosch process with an electrochemical system. Instead of using high temperature and pressure to drive the reaction, the invention uses electrocatalysis to facilitate nitrogen reduction at ambient conditions, substituting thermal-mechanical energy with electrical energy and catalytic action
Solution Approach 2:
The patent changes the operating parameters from high temperature and pressure to ambient conditions. By modifying the reaction conditions and using electrocatalysis, the system achieves nitrogen reduction at lower temperatures and pressures while maintaining acceptable yield rates
2Temperature
If electrochemical nitrogen reduction reaction is used, then ambient conditions are achieved, but low yield rate and competition with hydrogen evolution reaction occur
Solution Approach 1:
The patent applies local quality by creating specific surface conditions on the catalyst. The CuWO4 hollow nanospheres with oxygen vacancies and Mo cluster inclusions provide localized active sites with enhanced catalytic activity. This local modification allows the catalyst to selectively promote nitrogen reduction while suppressing hydrogen evolution, improving yield rate at ambient conditions
Solution Approach 2:
The patent uses composite materials by combining CuWO4 hollow nanospheres with Mo cluster inclusions. This composite structure integrates the advantages of both materials: the CuWO4 provides the hollow nanosphere framework with oxygen vacancies, while the Mo clusters enhance catalytic activity and selectivity for nitrogen reduction, overcoming the limitations of single-material catalysts
3Temperature
If electrochemical nitrogen reduction reaction is used, then ambient conditions are achieved, but competition with hydrogen evolution reaction reduces efficiency
Solution Approach 1:
The patent creates local quality through oxygen vacancies in the CuWO4 structure. These vacancies form specific active sites that selectively promote nitrogen reduction reactions. The localized electronic structure changes at oxygen vacancy sites enhance the catalyst's ability to distinguish between nitrogen reduction and hydrogen evolution pathways, improving reaction selectivity
Solution Approach 2:
The patent uses Mo cluster inclusions as intermediary elements that mediate the catalytic process. The Mo clusters act as co-catalysts that facilitate nitrogen reduction while suppressing hydrogen evolution. These intermediary structures modify the electronic properties of the CuWO4 surface, creating a more selective catalytic environment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The CuWO4 hollow nanospheres with Mo clusters exhibit high ammonia Faradaic efficiency of 94.60±3.75% and yield rate of 5.84±0.45 mg h−1 mgcat−1 at −0.7 V versus RHE, demonstrating improved selectivity and efficiency for nitrate reduction.
Implementation Method 1
forming a CuWO4 hollow nanosphere by a hydrothermal process followed by a thermal treatment
Implementation Method 2
plasma-treating the CuWO4 hollow nanosphere with a plasma to introduce oxygen vacancies
Implementation Method 3
the thermal treatment comprises annealing the precursor precipitate to form a CuWO4 hollow nanosphere
Data Source
AI summary
Electrochemical conversion of nitrate to ammonia is an approach to alleviate nitrate pollution in water and simultaneously generate green NH3 fuels. The practical application of this approach is challenging due to the lack of efficient electrocatalysts. The present disclosure relates generally to an electrocatalyst including a plurality of CuWO4 hollow nanospheres, which include asymmetric oxygen vacancies and adjacent Mo clusters, and methods of making and using the same. The electrocatalyst of the present disclosure is designed for efficient ammonia electrosynthesis.