  Developing colloidal plasmonic nanomaterials with high carrier density that
show optical resonances and photochemical activity extending from the visible
to the mid-infrared (MIR) ranges remains a challenging pursuit. Here, we report
the fabrication of titanium nitride (TiN) nanobars obtained using a two step
procedure based on a wet chemical route synthesis of TiO2 nanowires and their
subsequent high temperature annealing in ammonia flow. Electromagnetic
simulations of the resulting TiN nanobars reveal a rich set of optical
resonances featuring transverse, longitudinal and mixed transverse longitudinal
plasmonic modes that cover energies from the visible to MIR region. TiN
nanobars decorated with Pt co catalyst nanocrystals show enhanced
photocatalytic hydrogen evolution activity in comparison to both isotropic TiN
nanospheres of similar size and TiN nanocubes under near infrared excitation at
940 nm due to the enhanced hot electron generation. We also demonstrate that
plasmonic TiN nanobars can be used for the detection of furfural molecular
vibrations by providing a strong surface enhanced infrared absorption (SEIRA)
effect in the MIR region.
