Photocatalyst Production via Flux Calcination for Water Splitting
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Solution Overview
Problem
Conventional photocatalysts with yttrium replaced by other elements exhibit low water splitting performance, limiting the control of absorption wavelengths and durability.
Innovation Solution
A novel photocatalyst is produced by adding a chloride or iodide of specific elements like Li, Na, K, Rb, Mg, Ca, Sr, and Ba as a flux component and calcining at specific temperatures, enhancing photocatalytic activity and water splitting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the yttrium element of YTOS is replaced with another element, then absorption wavelength control is improved, but water splitting performance deteriorates
Solution Approach 1:
The patent applies local quality by introducing flux components (chlorides and iodides of specific elements) at localized positions during the calcination process. These flux components are mixed with raw materials at mass ratios of 0.01 to 50 times before calcination at 450°C to 1050°C, creating localized chemical environments that improve crystal formation and water splitting performance while maintaining the desired absorption wavelength characteristics through element replacement in the MaTibOcSd structure.
2Adaptability or versatility
If the yttrium element of YTOS is replaced with another element, then compositional flexibility is improved, but durability deteriorates
Solution Approach 1:
The patent applies parameter changes by systematically varying the calcination temperature (450°C to 1050°C) and the mass ratio of flux components (0.01 to 50 times) during the synthesis process. These parameter changes optimize the crystal structure formation and surface properties of the photocatalyst, enhancing both durability and water splitting performance while maintaining compositional flexibility through the MaTibOcSd structure where M can be various lanthanoid elements.
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 method significantly improves water splitting performance, enabling efficient production of hydrogen and oxygen using the photocatalyst with enhanced durability and stability.
Implementation Method 1
calcining a resultant product at 450° C. to 1050° C.
Implementation Method 2
adding a chloride or an iodide of a specific element as a flux component and performing calcination
Implementation Method 3
The water splitting reaction of a photocatalyst has been extensively studied for a long time
Implementation Method 4
the photocatalyst generates hydrogen in an amount of 100 μmol or more per hour by irradiating the photocatalyst with light
Data Source
AI summary
Provided is a photocatalyst with significantly enhanced water splitting performance in YTOS or in a composition in which the yttrium element of YTOS has been replaced with another element. Also provided is a method for producing a photocatalyst that has a composition represented by the following general formula (I), the method including mixing, with a raw material of the photocatalyst, a flux component at a mass ratio of 0.01 times to 50 times, the flux component being composed of one or more chlorides and/or iodides of at least one selected from Li, Na, K, Rb, Mg, Ca, Sr, and Ba, and calcining a resultant product at 450° C. to 1050° C.:MaTibOcSd (I)(where M is a combination of one or more selected from Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Y, a is a number of 1.7 to 2.3, b is a number of 2, c is a number of 4.7 to 5.3, and d is a number of 1.7 to 2.3).