Bandgaps and bandedges of the heterojunctions at pH = 0.

Structure	E g (eV)	E VBM (eV)	E CBM (eV)	Bandgap	Straddling water redox potentials
HfS2/h-BN	1.78	−6.51	−4.74	Direct	No
HfS2/h-BN with −6% strain	0.62	−5.77	−5.14	Direct	No
HfS2/h-BN with −3% strain	1.27	−6.21	−4.94	Direct	No
HfS2/h-BN with 3% strain	2.03	−6.63	−4.60	Direct	No
HfS2/h-BN with 6% strain	2.28	−6.71	−4.43	Direct	Yes
HfS2/h-BN with 9% strain	2.52	−6.80	−4.28	Direct	Yes
HfS2/g-C3N4	1.29	−7.19	−5.90	Direct	No
HfS2/g-C3N4 with −6% strain	0.01	−5.34	−5.33	Direct	No
HfS2/g-C3N4 with −3% strain	0.38	−5.60	−5.22	Direct	No
HfS2/g-C3N4 with 3% strain	1.92	−6.65	−4.73	Indirect	No
HfS2/g-C3N4 with 6% strain	2.29	−6.88	−4.59	Direct	No
HfS2/g-C3N4 with 9% strain	2.72	−7.15	−4.43	Indirect	Yes