Interaction of NO during cathodic polarization in alkaline conditions at the interface of Pt-nanostructures supported on C and TiO2-C

Sustainable NO removal and its sensitive monitoring at room temperature by electrogenerated Ni (I) electron mediator

Online monitoring of gas pollutants in the gas phase at room temperature using an electrochemical macro gas flow sensor is challenging and important for the pollutant treatment process. In this work, for the first time, we tried to explore the homogeneous and heterogeneous application of Ni(II) (CN)₄^2- in the KOH environment for the removal and monitoring of toxic nitric oxide gas. The homogeneous electrogenerated Ni(I) (CN)₄^3- was effectively removing the toxic nitric oxide gas by electro scrubbing method and the novel Ni(II) (CN)₄^2- and KOH modified electrode used for heterogeneous sensor application with high sensitivity, and reliability toward Nitric oxide gas. The sensor showed enhanced gas diffusion and high sensitivity. Scanning electron microscopy and X-ray diffraction confirmed the modification of the carbon felt electrode. In a high concentrated KOH environment, the active mediator stabilized the sensor for a long time compared to the neutral environment. The Ni(II) (CN)₄^2- fabricated carbon felt was used to monitor the concentration of nitric oxide gas pollutant; the calculated sensitivity was approximately -0.33 mA ppm^-1 cm^-2. The current increased linearly with increasing nitric oxide concentration up to 12 ppm and was validated by online gas chromatography. The developed electrochemical gas flow sensor successfully monitored the unremoved nitric oxide gas at the exit from the MER electro-scrubbing process; the concentration was calculated using a calibration plot.

Recent Progress in the Abatement of Hazardous Pollutants Using Photocatalytic TiO2-Based Building Materials

Titanium dioxide (TiO2) has been extensively investigated in interdisciplinary research (such as catalysis, energy, environment, health, etc.) owing to its attractive physico-chemical properties, abundant nature, chemical/environmental stability, low-cost manufacturing, low toxicity, etc. Over time, TiO2-incorporated building/construction materials have been utilized for mitigating potential problems related to the environment and human health issues. However, there are challenges with regards to photocatalytic efficiency improvements, lab to industrial scaling up, and commercial product production. Several innovative approaches/strategies have been evolved towards TiO2 modification with the focus of improving its photocatalytic efficiency. Taking these aspects into consideration, research has focused on the utilization of many of these advanced TiO2 materials towards the development of construction materials such as concrete, mortar, pavements, paints, etc. This topical review focuses explicitly on capturing and highlighting research advancements in the last five years (mainly) (2014-2019) on the utilization of various modified TiO2 materials for the development of practical photocatalytic building materials (PBM). We briefly summarize the prospective applications of TiO2-based building materials (cement, mortar, concretes, paints, coating, etc.) with relevance to the removal of outdoor/indoor NOx and volatile organic compounds, self-cleaning of the surfaces, etc. As a concluding remark, we outline the challenges and make recommendations for the future outlook of further investigations and developments in this prosperous area.