Ordered NiO Nanowire Array Doped with Pt for Gas Sensing
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Solution Overview
Problem
Existing gas sensors for hydrogen detection, such as semiconductor gas sensors based on metal oxides, face challenges with selectivity and operating temperature, and require improved sensitivity and stability, particularly for hydrogen detection.
Innovation Solution
A method for manufacturing an ordered nanowires array of NiO doped with Pt in situ, involving the growth of a Ni layer on a substrate, patterning with electron beam etching, displacement reaction with H2PtCl6, and thermal oxidation to form NiO nanowires with enhanced sensitivity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor gas sensors based on metal oxide are used for hydrogen detection, then the sensor can detect hydrogen gas, but the selectivity is poor and operating temperature is high
Solution Approach 1:
The patent changes the physical state and dimension parameters of NiO from bulk to nanowire structure, and further to ordered array configuration. This dimensional transformation reduces the operating temperature from typical semiconductor sensor temperatures (>200°C) to lower temperatures while maintaining detection capability, and the ordered array structure improves selectivity through controlled surface area and active sites
Solution Approach 2:
The patent creates a composite structure by doping NiO with Pt (platinum) to form NiO-Pt composite nanowires. The Pt dopant acts as catalytic sites that enhance selectivity for hydrogen detection, while the NiO matrix provides the semiconductor sensing mechanism. This composite approach allows operation at reduced temperatures with improved selectivity
2Reliability
If the dimension of NiO is reduced to nanometers, then sensitivity is improved due to surface area to volume ratio, but manufacturing precision and control become more difficult
Solution Approach 1:
The patent employs a two-stage manufacturing approach where Ni nanowires are first grown on a substrate with controlled geometry, and then oxidized in situ to form NiO nanowires. This preliminary formation of Ni nanowires with defined structure before oxidation allows precise control over the final NiO nanowire array dimensions and ordering, enabling sensitivity improvement while maintaining manufacturing precision
Solution Approach 2:
The patent replaces complex top-down mechanical fabrication methods with a bottom-up chemical growth approach using electron beam evaporation and in situ oxidation. This substitution allows self-organized formation of ordered nanowire arrays with precise dimensional control at the nanometer scale, achieving both high sensitivity and manufacturing precision
3Reliability
If Pt is doped into NiO to enhance sensitivity and selectivity for H2, then the sensor performance is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the doping process with the nanowire formation process by performing in situ oxidation during the electron beam evaporation sequence. Pt is introduced as PtCl6 2- ions in the vapor phase during Ni oxidation, combining material deposition, nanowire formation, and doping into a single integrated process step, thereby reducing overall manufacturing complexity while achieving enhanced sensitivity and selectivity
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 achieves improved sensitivity and reliability for detecting hydrogen and carbon monoxide gases with reduced operating temperature and power consumption, while being simple and controllable.
Implementation Method 1
an electron beam evaporation or a magnetron sputtering may be utilized, in which the conditions for the electron beam evaporation are as follows: a vacuum of 10−4 ̃10−6 Torr, a temperature of 1100-1600° C., an evaporation rate of 0.1-3 nm/s
Implementation Method 2
the conditions for the magnetron sputtering are as follows: a voltage of 400 ̃800V, a magnetic field strength of 70 ̃300 G, an air pressure of 1-10 mTorr, a current density of 5 ̃60 mA/cm, a power density of 1 ̃40 W/cm, and a maximum sputtering rate of 100 nm ̃1000 nm
Implementation Method 3
pattering a pattern region of the ordered nanowires array by applying electron beam etching on the photoresist
Implementation Method 4
etching the surface of the Ni layer by ion beam etching so as to etch off the Ni layer grown on the surface of the substrate and to leave the Ni on the pattern region of the ordered nanowires array
Implementation Method 5
dipping the ordered Ni nanowires array into a solution of H2PtCl6 so as to displace Pt on the Ni nanowires array by a displacement reaction
Implementation Method 6
oxidizing the Ni nanowires array attached with Pt in an oxidation oven to obtain the ordered nanowires array of NiO doped with Pt
Data Source
AI summary
The present disclosure provides a method for manufacturing ordered nanowires array of NiO doped with Pt in situ, comprising: growing a Ni layer on a high-temperature resistant and insulated substrate; applying a photoresist on the Ni layer, pattering a pattern region of the ordered nanowires array by applying electron beam etching on the photoresist, growing Ni on the pattern region of the ordered nanowires array, peeling off the photoresist by acetone and etching the surface of the Ni layer by ion beam etching so as to etch off the Ni layer grown on the surface of the substrate and to leave the Ni on the pattern region of the ordered nanowires array to form the ordered Ni nanowires array; dipping the ordered Ni nanowires array into a solution of H2PtCl6 so as to displace Pt on the Ni nanowires array by a displacement reaction; and oxidizing the Ni nanowires array attached with Pt in an oxidation oven to obtain the ordered nanowires array of NiO doped with Pt. The present invention is simple and practical and the sensitivity and reliability of the doped sensor on the gas of CO and H2 are greatly improved.