Ferroso-ferric oxide (Fe3O4) embedded g-C3N4 nanocomposite sensor fabricated by photolithographic technique for environmental pollutant gas sensing and relative humidity characteristics

[Display omitted] •The effective nanocomposite C3N4/Fe3O4 fabricated by cost effective co-precipitation method.•The photolithographic technique involving 40 s size, having mesh number 355 was utilized to fabricate film sensor.•Mechanism for testes gases CO and NO2 is established.•Comparative reports of bare Fe3O4 and modified Fe3O4.•Synergetic effect of C3N4 and Fe3O4, makes modified sensor as an effective sensor for tested gases. The research portrayed in the present investigation of gas sensing and humidity sensing characteristics of the screen printed thick film sensors. The materials bare Fe3O4 and C3N4/Fe3O4 were fabricated by conventional co-precipitation and heat treatment method. The prepared materials were characterized of series of nanomaterial characterization techniques such as X-ray diffraction (XRD) technique to confirm structural parameters, scanning electron microscopy (SEM) for topographic and surface characterization of the fabricated materials, while energy dispersive spectroscopy (EDS) was utilized to confirm elemental composition. High resolution transmission electron microscopy (HR-TEM) was employed to confirm the lattice parameters of the fabricated materials. The magnetic properties were investigated from vibrating sample magnetometer (VSM), additionally the elemental composition and chemical states of the prepared materials was confirmed from X-ray photoelectron spectroscopy (XPS) technique. The thick film sensors of the fabricated materials Fe3O4 and C3N4/Fe3O4 were prepared by standard photolithographic technique. The thick film sensors were employed for gas sensing characteristics of the gases such as CO, NO2, CO2,tolune vapours (TV) and dichloromethanne vapours (DCM). Out of that the C3N4/Fe3O4 sensor showed excellent gas response of 85.25 % for CO and 75.80 % for TV at 1000 ppm gas concentration. The overall gas sensing properties such as selectivity, response recovery and temperature effects and ppm variation of the gases were investigated in detailed. Additionally, the fabricated sensors were also explorated for humidity sensing properties. As per the data of gas sensing, the modified C3N4/Fe3O4 is observed to be promising and stable sensor to sense the CO and TV vapors at moderate temperature and humid conditions.