Hide "There are no products to display" in an empty category

There are two options to achieve this result.

Find this text in your language file which is under Settings > Store settings > Languages. Edit your online language file.
Once you've found the text, on the replacement field just use the space bar once and save.
Place the following code in your header and save.

<script> // hide "There are no products to display" in an empty category

$(document).ready( function() {

if ($('#ctl00_CenterSection_w1_ProductRepeater_ctl01_divNoItem').length) {

$('.products-title').hide();

$('#ctl00_CenterSection_w1_ProductRepeater_ctl01_divNoItem').hide();

}

});

</script>