Gas sensing using porous materials for automotive applications

Abstract

Improvements in the efficiency of combustion within a vehicle can lead to reductions in the emission of harmful pollutants and increased fuel efficiency. Gas sensors have a role to play in this process, since they can provide real time feedback to vehicular fuel and emissions management systems as well as reducing the discrepancy between emissions observed in factory tests and 'real world' scenarios. In this review we survey the current state-of-the-art in using porous materials for sensing the gases relevant to automotive emissions. Two broad classes of porous material - zeolites and metal-organic frameworks (MOFs) - are introduced, and their potential for gas sensing is discussed. The adsorptive, spectroscopic and electronic techniques for sensing gases using porous materials are summarised. Examples of the use of zeolites and MOFs in the sensing of water vapour, oxygen, NOx, carbon monoxide and carbon dioxide, hydrocarbons and volatile organic compounds, ammonia, hydrogen sulfide, sulfur dioxide and hydrogen are then detailed. Both types of porous material (zeolites and MOFs) reveal great promise for the fabrication of sensors for exhaust gases and vapours due to high selectivity and sensitivity. The size and shape selectivity of the zeolite and MOF materials are controlled by variation of pore dimensions, chemical composition (hydrophilicity/hydrophobicity), crystal size and orientation, thus enabling detection and differentiation between different gases and vapours.

Photoluminescent Metal–Organic Frameworks for Gas Sensing

“…Similar with common luminescent materials, the luminescence of MOFs can be influenced by many environmental factors,3, 4 including physical stimulus and chemical stimulus (ions,30, 31, 32, 33 solvents,34, 35, 36 vapors,37 pH,38, 39 gases,1 and so on40, 41, 42, 43, 44, 45). However, unlike other luminescent materials, the intrinsic porosity, large surface area, and strong adsorption affinity of MOFs can effectively enrich guest species.…”

“…Therefore, when luminescent MOFs are used for gas‐phase sensing, gas analytes are generally presented as saturated vapors, and only the emission colors (frequencies/wavelengths) are compared in detail. Nevertheless, the fast increasing number of MOF materials and their thin‐film fabrication techniques,54, 55, 56 coupled with the ever growing demand for accurate detection of the chemical information of air and many gaseous environments,1, 57, 58, 59, 60, 61 have stimulated more and more studies using luminescent MOFs as sensing materials for the gas environment 46, 62, 63, 64…”

The Analysis and Research for the Plate Differential Oxygen Gas Sensor of Auto Based on the Temperature Field and Thermal Stress Field

“…Among them, the exhaust gas emitted by automobiles is a major air pollution source in the world, which seriously affects the ecological environment and people's physical and mental health [4].At present, the electronic injection system has replaced the traditional carburetor as the fuel supply mode of the automobile engine. Among them, the automobile oxygen sensor is the detection element in the closed-loop control system of EFI engine [26]. It is one of the key components to improve the combustion efficiency of automobile engines, control the exhaust emissions of automobiles and reduce the environmental pollution caused by automobiles [27].According to statistics, most of the automotive oxygen sensor design life is 60 thousand km [28].…”

Gold Nanoparticle Treated Textile-Based Materials for Potential use as Wearable Sensors

“…A wide variety of materials including polymers, ferroelectric ceramics, piezoelectric semiconductors and shape memory films have been studied and used to manufacture an assortment of chemical sensors [1][2][3]. These sensors have been used in a wide variety of applications such as gas detection, food processing, cosmetics and pharmaceuticals [4][5][6][7][8].…”