We synthesized zinc oxide-reduced graphene oxide (ZnO-rGO) composites using a one-pot chemical deposition method at room temperature. Zinc powder and graphene oxide (GO) of different mass ratios (1 : 1, 1 : 2, 1 : 5, 1 : 10, and 1 : 20 GO to Zn) were used as precursors in a mildly alkaline solution. UV-Vis spectroscopy was used to study the photocatalytic efficiency of the samples through the photodegradation of methylene blue (MB). UV-Vis measurements show the fast decomposition of methylene blue under UV light illumination with the best degradation efficiency of 97.7% within one hour, achieved with sample ZG2 (1 GO : 2 Zn mass ratio). The corresponding degradation rate was k_ZG2 = 0.1253 min⁻¹, which is at least 5.5 times better than other existing works using hydrothermal methods. We argue that the excellent photodegradation of MB by ZG2 is due to the efficient charge separation brought about by the electronic interaction of the rGO with the ZnO and the formation of a Zn-O-C bond, as supported by XRD and Raman spectroscopy measurements.

We demonstrate that a planar single-walled carbon nanotube (SWCNT) film bolometer can exhibit enhanced thermal and optical properties. The SWCNT film were ink-printed on an oxidized silicon substrate between two pointed-tip Au electrodes across a gap of approximately 10 μ m. We obtained a bolometer figure-of-merit temperature coefficient of resistance of greater than –3.0% at room temperature. An optical response of 1000 V W ⁻¹ was obtained from a 786 nm laser with an output power of 5 mW. The corresponding thermal time constant of 1.8 ms was estimated through the optical response by modulating the laser over a frequency range of 1 Hz–1 kHz. The optical noise equivalent power and optical detectivity of 4.5 × 10 − 11 W / Hz and 4.9 × 10 8 cm Hz W − 1 , respectively, were estimated from the responsivity, the spectral density, and area of the cell of the absorber, 4.9 × 10 ⁻⁴ cm ² . We attribute the exceptional performance of the SWCNT microbolometer to the film nature of the absorber and to the high concentration of the incident electromagnetic radiation and localized heating between the tips of the electrode.

Calophyllum inophyllum (CI) oil was used as precursor source material in carbon nanomaterial synthesis. CI is a non-edible and native plant species in the Philippines, which makes production of seeds and kernel sustainable. An atmospheric pressure chemical vapor deposition system was designed and built for the synthesis. Different carbon-based nanostructures were synthesized by varying the Argon gas flow rates (3.5–5 liter/min) and temperatures (1000–1200 °C). Crystalline multiwalled nanofibers and iron carbide-encapsulated nanocapsules were formed at 1000 °C and a gas flow rate of 5 liter/min. On the other hand, oils synthesized at 1100–1200 °C produced amorphous film-like carbon materials. The different morphologies reflect the influence of the gas flow rate on the dilution and atomization of the oil and its decomposition at various temperatures used. Raman spectroscopy and surface potential measurements indicate the potential applications of these nanofibers for hydrogen storage and semiconducting devices.